Saturday, 8 February 2020

UPPER CRETACEOUS NANAIMO GROUP AT HORNBY ISLAND

Hornby is a delightful island off the east coast of Vancouver Island, just east of Denman Island. Texada and Lasqueti lie just to the west of Hornby. It is home to about 1,000 residents made up of artists, retirees and those wanting to enjoy the quiet, rural, community-oriented lifestyle.

Hornby Island is formed from sediments of the upper Nanaimo Group which are also widely exposed on adjacent Denman Island and the southern Gulf Islands. Peter Mustard, a geologist from the Geologic Survey of Canada, did considerable work on the geology of the island. It has a total stratigraphic thickness of 1350 m of upper Nanaimo Group marine sandstone, conglomerate and shale.

These are partially exposed in the Campanian to the lower Maastrichtian outcrops at Collishaw Point on the northwest side of Hornby Island. Four formations underlie the island from oldest to youngest, and from west to east: the Northumberland, Geoffrey, Spray and Gabriola.

During the upper Cretaceous, between ~90 to 65 Ma, sediments derived from the Coast Belt to the east and the Cascades to the southeast poured seaward to the west and northwest into what was the large ancestral Georgia Basin. This major forearc basin was situated between Vancouver Island and the mainland of British Columbia.

The island's soils have developed from marine deposits of variable texture, except for the higher elevations and steeper slopes where weathered clastic sedimentary rock provides the parent material. Most of Hornby's soils are sandy or gravelly, but some deep black loams occur in the northwestern part and many of the sands at the southern end have loam-textured topsoils.

Collishaw Point, known locally as Boulder Point, Hornby Island
Podzols are common and the bleached sand grains associated with their eluvial (A2, Ae or E) horizons lend a salt-and-pepper appearance to many forest trails. In most cases, though, the E is not very thick and may, in fact, be discontinuous. For this reason, the soils were mostly classified as Brown Podzolic in a soil survey published in 1959.

All of the island's soils are strongly acidic in their natural state except for those which have developed on shoreline shell middens.

And it is to the shore that many are drawn — locals, tourists, geologists and paleontologists alike. Hornby is a wonderful place to explore. The island is beautiful in its own right and the fossils from here often keep some of their original shell or nacre which makes them quite fetching.

The Nanaimo Group as a whole represents largely coarse-grained units deposited in deep-sea fan systems. In this environment, deeper channels continuously cut through successive shale and sandstone bodies. The channels funnelled density currents into the basin, while also building levee deposits. Turbidity currents travelled down the channels, and also overtopped the levees spilling across backslope areas. The sequential sediment formations, from significantly coarse-grained sandstones and conglomerates to fine silts and shale units of the Nanaimo Group, are considered to be partly due to eustacy, but more significantly related to relative sea-level changes induced by regional tectonics in an active forearc setting.

The Northumberland Formation consists of a massive, dark-grey mudstone which is locally interlaminated and interbedded with siltstone and fine-grained sandstone.

There are abundant calcium carbonate concretions, parallel and current ripple laminations, clastic dikes and folded layers due to slumping. In the Gulf Islands to the south, this formation has been found to contain abundant and diverse foraminifera indicating marine paleodepths of 150-1200 m.

The more resistive Geoffrey Formation consists of thick-bedded sandstone and conglomerate. It is highly channelized, and some sandstone has exposed parallel and ripple laminations. The Spray Fm exposed on the east end of the island is a massive olive-grey mudstone with interlaminations of sandstone.

Furthest to the east, the youngest exposures on Hornby Island are from the Gabriola Formation, which outcrops on the eastern peninsula. This is again a thick-bedded and channelized sequence of conglomerates and massive sandstone with minor mudstone interbeds. South, in the Gulf Islands, this formation has contained ammonites, gastropods and pelecypods. Paleowater-depth from foraminiferal assemblages has been set at 200 m.

Katnick, D.C. and P.S. Mustard (2001): Geology of Denman and Hornby Islands, British Columbia (NTS 92F/7E, 10); British Columbia Geological Survey Branch, Geoscience Map 2001-3.

England, T.D.J. and R. N. Hiscott (1991): Upper Nanaimo Group and younger strata, outer Gulf Islands, southwestern British Columbia: in Current Research, Part E; Geological Survey of Canada, Paper 91-1E, p. 117-125.

Thursday, 6 February 2020

LIVING FOSSIL: HEDGEHOGS

This little cutie is a Western European hedgehog, Erinaceus europaus, in the subfamily Erinaceinae (Fischer, 1814). They are native to western Europe, Asia, Africa and have been introduced (oops!) to New Zealand.

There are seventeen species of hedgehog in five genera. They share distant ancestry with the family Soricidae (shrews) and the gymnures.

Hedgehogs are considered "Living Fossils" as they have changed very little over the past 15 million years. These small mammals are loners with their own kind but live in close proximity to our human population. They dwell in inhabited areas, farmland, deciduous forests and desert. You'll know them by their distinctive spiny look (which may remind you of very tasty chocolates from Purdy's in Canada) and their adorable piglike snorts and grunts as they make their way through the underbrush looking for tasty snacks.

Look for them in the evening in hedgerows and undergrowth as they hunt for frogs, toads, snails, bird eggs, grassroots, berries, insects, worms and snakes. They fatten themselves up in preparation for hibernation. They'll find a nice burrow or built a nest in leaves or compost heaps. In Europe, they generally hibernate by October or November and become active again in March to mid-April once temperatures reach over 15 degrees.

Wednesday, 5 February 2020

JURASSIC STILL LIFE

This beautiful block, an ancient Still Life of the Jurassic (Callovian) hails from outcrops near Anwil, a municipality in the district of Sissach in the canton of Basel-Country in Switzerland.

It is a tremendous block showing the fauna from that time. Ammonites and Trigonia are clustered together. This specimen was found and prepared by the talented Tim Haye. Tim made the find during his inspection of a 2014 excavation through the Bern and Basel Museums.

Tuesday, 4 February 2020

PALEONTOLOGIE FRANCAISE

Paléontologie Française: Alcide d'Orbigny

L'un des grands classiques, Paléontologie Française: Zoologique Et Géologique de Tous les Animaux Mollusques Et Rayonnés Fossiles de France, Comprenant Leur Application A la Reconnaissance des Couches; Terrains Crétacés, Supplément. Voici une citation de cette édition:

"Eepl. Des fig. Pl. 4, fig. 4, cône alvéolaire de grandeur naturelle, vu de profil; a la tige: la partie ombrée est ce qu'on connaît en nature, le reste est supposé fig.

Le même, vu en dessus; fig. 3, godet terminal, supposé d'après les lignes d'accroissement; fig. 4, coquille entière, supposée d'après les lignes d'accroissement marquées sur le cône alvéolaire; fig. 5, la figure 2 grossie, la partie non ombrée supposée; fig. 6, la figure grossie; et, partie supposée; b, partie positive; fig. 7, cône alvéolai're vu en dessus, avec son siphon ventre, de ma collection."

Monday, 3 February 2020

PRIMITIVE PTERASPIDOMORPHS

The oldest and most primitive pteraspidomorphs were the Astraspida and the Arandaspida.

They evolved in shallow equatorial seas, as a large diverse and widespread group of armoured, jawless fishes: the Pteraspidomorphi. The first of three groups of ostracoderms.

The Pteraspidomorphi are divided into three major groups: the Astraspida, Arandaspida and the Heterostraci. You'll notice that their taxon names contain 'aspid', which means shield. This is because these early fishes and many of the Pteraspidomorphi possessed large plates of dermal bone at the anterior end of their bodies. This dermal armour was very common in early vertebrates, but it was lost in their descendants.

Arandaspida is represented by two well-known genera: Sacabampaspis, from South America and Arandaspis from Australia. Arandaspis have large, simple, dorsal and ventral head shields. Their bodies were fusiform, which means they were shaped sort of like a spindle, fat in the middle and tapering at both ends. Picture a sausage that is a bit wider near the centre with a crisp outer shell.

Photo by Nobu Tamura (http://spinops.blogspot.com) - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19460450

Sunday, 2 February 2020

JUVENILE HAMITES SUBROTUNDUS

A tremendously delicate juvenile Hamites subrotundus (J. Sowerby 1814) from Upper Albian outcrops in Mallorca, the largest of the Spanish Balearic Island in the Mediterranean. It is famous for its limestone mountains and Roman and Moorish remains. As you can see here, it is also home to some rather nice fossils including this specimen of Hamites subrotundus.

While H. subrotundus is generally a Middle Albian species, this specimen was found in the lower part of Upper Albian in the Cristatum zone by José Juárez Ruiz. José had to piece this lovely together from seven fragments. His labour of love was worth the effort. The final piece is sheer perfection and a beautiful specimen approximately 2.5 cm long.

Mallorca and the other Balearic Islands are geologically an extension of the Betic Cordillera of Andalusia. They are made up of sediments deposited in the Tethys Sea during the Mesozoic.

Exploring the islands, you can collect from deposits from the Triassic, Cretaceous, Jurassic, and Neogene periods. The limestone outcrops contain many foraminifers of the species Globigerina.

We also see lovely examples of Hamites (Hamites) subrotundus in the Euhoplites loricatus zone; Euhoplites meandrinus subzone from the Middle Albian (Lower Gault) of Folkestone, Kent, UK. Photo, preparation and in the collection of the deeply awesome José Juárez Ruiz. Wright C. W. 1996. Treatise on Invertebrate Paleontology (Part L Mollusca 4 Revised) Volume 4: Cretaceous Ammonoidea

Tuesday, 28 January 2020

GRAPTOLITES: DARLINGS OF THE DARRIWILIAN

Back in 2009, Jörg Maletz from St. Francis Xavier University, Antigonish, Nova Scotia, did a paper looking at the Les Méchins region in Quebec to compare the Darriwilian graptolite succession found there against other outcrops of eastern North America.

The graptolite faunas of the upper member of the Anse au Crapaud Formation include the Arienigraptus gracilis, Oncograptus upsilon, Undulograptus austrodentatus, and Holmograptus spinosus biozone faunas and, thus, complement the well known Darriwilian faunas of the Cow Head, Table Head, and Goose Tickle groups of western Newfoundland. In particular, the Holmograptus spinosus Biozone interval of calcarenitic limestones bears a rare combination of benthic (shelly) and planktic (graptolitic) faunas with conodonts, brachiopods, ostracods, sponge spicules, and algal remains associated with common graptolites that allow an inter-continental correlation.

The Holmograptus spinosus Biozone is introduced for the interval based on a diverse and characteristic graptolite fauna. The fauna includes among others, Atopograptus woodwardi, recognized for the first time in North America. The Holmograptus spinosus Biozone fauna can be found worldwide and is easily correlated into the conodont biofacies using species of the genus Histiodella. He looked at ties between graptolite and conodont biozonations for the Darriwilian. Some lovely silicified ostracods were illustrated for the first time from the interval and a new species, Hustedograptus quebecensis, was introduced.

The Darriwilian or late Middle Ordovician time interval shows a dramatic re-organization of graptolite faunas, both in their taxonomic composition and in their rhabdosome developmental style.

The Early Ordovician graptolite faunas, composed of multiramous to pauciramous “Dichograptaceans” (Bulman 1970), are slowly replaced by dipleural biserial graptolites of the “Diplograptaceans” (Mitchell et al. 1995, 2007) or Axonophorans (Maletz et al. 2009).

This shift started with the introduction of the reclined isograptids and glossograptids in the Dapingian and culminated with the extinction of multiramous sinograptids and stem reclinatids in the Darriwilian (Da 2 – Da 3), leaving but few survivors to reach the Late Ordovician. The monopleural glossograptids, as a second clade of the Bireclinata, enjoyed moderate success in the mid and Late Ordovician, but never attained the high diversity of the Axonophorans.

The Darling Darriwilian


The Darriwilian is a significant stage in the Middle Ordovician. It is here we see the first land plants and the introduction of the Undulograptus austrodentatus graptolite zone. These graptolite outcrops from around the world help us establish the base of the Darriwilian as an easily correlatable marker in time. Yet, for so many reasons, the charming Darriwilian has not received the attention in graptolite studies it deserves and little is known about many of the graptolites from the interval.

The biostratigraphy within this time interval remains only partially explored due to a scarcity of uninterrupted successions. The Darriwilian in Victoria, Australia (Vandenberg and Cooper 1992) is based on numerous spot collections, but successions spanning more than a single graptolite zone are not available. The base of the Darriwilian is now defined at the first appearance datum (FAD) of Undulograptus austrodentatus in the Huangnitang section (Zhejiang, China), but the graptolitic succession is less detailed and complete in the higher part of the interval (see Chen et al. 2006).

The northern Appalachian successions in Quebec and western Newfoundland provide numerous successions from which detailed biostratigraphical data are available, but most sections are poorly studied. Recent advances show the presence of good Darriwilian graptolite faunas in the Cow Head, Table Head, and Goose Tickle groups of western Newfoundland (Williams and Stevens 1988; Maletz 1992c; Taylor 1997) and China (Chen et al. 2006) that provide a better insight into the biostratigraphy and evolutionary history of graptolites in this interval.

Lithostratigraphic Succession at Les Méchins


The southern shore of the St. Lawrence River along the coast of the Gaspé Peninsula of Quebec exposes Cambrian to Ordovician continental slope sequences, representing the allochthonous thrust slices of the Humber tectonostratigraphic zone of Williams (1979). The successions were thrust westwards across the eastern rim of Laurentia during the Taconic Orogeny in the Middle Ordovician. Because of the complexity of the successions, the stratigraphy is only well defined in part and detailed biostratigraphic work is lacking for most regions.

Bernstein et al. (1992) described the lithostratigraphic succession at Les Méchins and provided detailed information on the location of the sections along the northern side of route 132, directly west of the entrance to Les Méchins.

As graptolites are the most important biostratigraphic indicators, their record can shed light on the structural complexity of the successions and help us to understand the geological evolution of this region. Newly discovered faunal successions at Les Méchins, Quebec have provided important biostratigraphical and biogeographical data and yielded taxa not previously found in North America.

Maletz, Jörg. Holmograptus spinosus and the Middle Ordovician (Darriwilian) graptolite biostratigraphy at Les Méchins (Quebec, Canada) Canadian Journal of Earth Sciences, 2009, 46:739-755, https://doi.org/10.1139/E09-048.

Albanesi, G., Hünicken, M.A., and Barnes, C.R. 1998. Bioestratigrafia de conodontes de las secuencias ordovicicas del Cerro Potrerillo, Precordillera central de San Juan, R. Argentina. Actas XII Academia Nacional de Ciencias., Córdoba, 12, pp. 7–72.

Bulman, O.M.B. 1970. Graptolithina with sections on Enteropneusta and Pterobranchia. In Treatise on invertebrate paleontology, Part V. 2nd ed. Edited by K. Teichert and R.C. Moore. Geological Society of America and University of Kansas Press, Boulder, Colo. and Lawrence, Kans., pp. 1–163.

Chen X, Zhang YD, Bergström SM, Xu H-G. 2006. Darriwilian graptolite and conodont zonation in the global stratotype section of the Darriwilian stage (Ordovician) at Huangnitang, Changshan, Zhejiang, China. Palaeoworld 15(2): 150-170.

Monday, 27 January 2020

ARIENIGRAPTUS OF BOLIVIA

Graptolites (Graptolita) are a group of colonial animals known primarily from Ordovician deposits. The biological affinities of the graptolites have always been debatable.

Originally regarded as being related to the hydrozoans, graptolites are now considered to be related to the pterobranchs, a rare group of modern marine animals.

The graptolites are classed as hemichordates (phylum Hemichordata), a phylum of marine deuterostome animals and come in a variety of weird and wonderful designs. They were a major component of the zooplankton in our early Paleozoic ecosystems, most likely living as suspension feeders, drifting freely on the surface of ancient seas or attached to floating seaweed by means of a slender thread. Some forms of graptolite lived attached to the sea-floor by a root-like base. The deceased planktonic graptolites would sink down to and settle on the seafloor, eventually becoming entombed in the sediment and are thus well-preserved.

Graptolite fossils are often found in shales and slates and can be mistaken for scratches on the rock. The name graptolite comes from the Greek graptos meaning "written", and lithos meaning "rock." It is a very suitable name as many graptolites look very much like hieroglyphs written on rock and not the impressions of animals.

Graptolites are common fossils and have a worldwide distribution. The preservation, quantity and gradual change over a geologic time scale of graptolites allow the fossils to be used to date strata of rocks throughout the world. They are important index fossils for dating Palaeozoic rocks as they evolved rapidly with time and formed many different species.

We find graptolite fossils flattened along the bedding planes of the rocks in which they occur. My first graptolite finds were from roadcuts up near Cranbrook, British Columbia, Canada. I was on a fossil field trip looking for Cambrian trilobites. It was a thrilling experience and completely unexpected when the first graptolite met my eyes.

They vary in shape, but are most commonly dendritic or branching (such as Dictoyonema), saw-blade like, or "tuning fork" shaped, such as Didymograptus murchisoni. The lovely specimen of Arienigraptus sp. you see here is from the Lower Darriwilian of Bolivia and in the collections of the deeply awesome Gilberto Juárez Huarachi‎. The second photo is from the Encyclopaedia Brittanica - From the Encyclopaedia Brittanica, Public Domain, https://commons.wikimedia.org/w/index.php?curid=6886878

Sunday, 26 January 2020

PERSISTISTROMBUS LATUS

A beautiful example of two water-worn specimens of the gastropod Persististrombus latus (Gmelin, 1791) captured after a storm captured by the deeply awesome José Juárez Ruiz from Palma De Mallorca, Spain.

In his original description of Strombus latus, Gmelin describes this new species in his paper from 1791, page 3520: "latus. 35. Str. testae labro prominulo inferne bis emarginato, spirae anfractu primo medio laevi utrinque transversim striato, reliquis nodis obtusis coronatis."

Persististrombus latus is the most iconic representative of the Senegalese fauna, a fossil assemblage of tropical water organisms thought to have colonized the Mediterranean Sea during the last interglacial period.

Persististrombus latus has become an important stratigraphic marker of Marine Isotope Stage (MIS) 5.5, which allows for the correlation of raised coastal deposits, useful in studying sea-level variations and tectonic uplift.

Persististrombus latus is found in shallow marine sediments of Tyrrhenian age (∼124 ka) in several localities of the Italian peninsula. Gmelin's early work on the species is from upper Pleistocene deposits of the marine terraces of the Crotone peninsula of southern Italy. If you fancy a visit to this locality, head to: N38°45'00" - N39°04'60", E17°04'60" - E17°19'60".

Commonly known as the Bubonian Conch, this species of sea snail is a marine gastropod mollusk in the family Strombidae, the true conchs. These fellows are herbivorous, dining on wee bits of algae, seagrass and other detritus found along the seafloor. They grow to around 2.76" - 6.5" (7cm - 16.5cm). We find them in the fossil record and also as modern shells in the Atlantic Ocean along West Africa, Senegal, Gabon, Cape Verde, Ascension Island and Angola. They like it warm, preferring seas of 57.2 °F - 68 °F (14°C - 20°C).

Ronald Nalin, Valentina Alice Bracchi, Daniela Basso, Francesco Massari; Persististrombus latus (Gmelin) in the upper Pleistocene deposits of the marine terraces of the Crotone peninsula (southern Italy). Italian Journal of Geosciences ; 131 (1): 95–101. doi: https://doi.org/10.3301/IJG.2011.25

Gmelin J.F. (1791). Vermes. In: Gmelin J.F. (Ed.) Caroli a Linnaei Systema Naturae per Regna Tria Naturae, Ed. 13. Tome 1(6). G.E. Beer, Lipsiae [Leipzig]. pp. 3021-3910.

Thursday, 23 January 2020

BAETIC CORDILLERA

This beautiful ammonite is Neocomites (Teschenites) flucticulus (Thieuloy, 1977) sharing a large boulder with a delicate, straight-shelled, heteromorph ammonite Bochianites. These beauties were found on a fossil field trip to Hauterivian, Early Cretaceous deposits in the Baetic Cordillera in the Spring of 2019. The Baetic Cordillera is one of the main systems of mountain ranges in Spain along the southern and eastern Iberian Peninsula. There are several productive outcrops here that yield lovely Cretaceous ammonites and other marine species.

Neocomites are known from about a dozen offshore marine deep subtidal Cretaceous deposits in France, Hungary, Italy, Romania, Slovakia and Ukraine. We also find Neocomites in the Cretaceous of British Columbia, Canada.

This lovely specimen is the first Neocomites I've seen come out of fossil deposits in Spain. It was found and prepped by the talented Manuel Peña Nieto of Córdoba, Spain.

Wednesday, 22 January 2020

RHACOLEPSIS AND CARDIAC OUTFLOW

This concretion contains a partially exposed Rhacolepis Buccalis, an extinct genus of ray-finned fossil fish in carbonate concretion from the Lower Cretaceous, Santana Formation, Brazil.

These ancient fish swam our Cretaceous seas 122-109 million years ago. Interestingly, we've been able to recover complete fossilized hearts from this species using X-ray synchrotron microtomography.

Lara Maldanis and her team published a paper on this back in 2016. They were looking at the evolution of cardiac outflow tracts in vertebrates and had a breakthrough moment when an x-ray revealed enough detail to show that Rhacolepis hearts contain a conus arteriosus containing at least five-valve rows making them a transitional morphology between the primitive, multivalve, conal condition and the derived, monovalvar, bulbar state of the outflow tract in modern actinopterygians.

Le premier et unique géoparc mondial UNESCO est situé dans le Cariri du Ceará (géoparc Araripe), dans l'intérieur semi-aride de la région Nordeste, Brésil. Reference: Maldanis et al. (2016) Heart fossilization is possible and informs the evolution of cardiac outflow tract in vertebrates.

Tuesday, 21 January 2020

SONGS OF THE CETACEAN

A mother humpback and her young charge. Mothers show a tremendous amount of affection and love to their young, often swimming so close together they touch noses.

The calves nurse for almost a year, growing slowly. Once nursed, they keep growing for another 8-10 years before reaching their full adult length. They grow up to 19 metres long and can weigh up to 40 tons (36 metric tons). 

Male humpbacks are known for their singing. They produce some of the most complex “songs” in the animal kingdom. We have recorded many of their high-pitched squeals, whistles and low, rumbling gurgles. Perhaps the males believe that those with the best vocal abilities attract the best mates. They certainly increase the connectedness of those living in their pod.

Humpback whales, Megaptera novaeangliae, are a species of baleen whale for whom I hold a special place in my heart. 

Baleens are whales who feed on plankton and other wee oceanic tasties that they consume through their baleens, a specialised filter of keratin that frames their mouths. There are fifteen species of baleen whales. They inhabit all major oceans, in a wide band running from the Antarctic ice edge to 81°N latitude.

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, whales are known as g̱wa̱'ya̱m. Both the California grey and the Humpback whale live on the coast. Only a small number of individuals in First Nation society had the right to harpoon a whale. It was generally only the Chief who was bestowed this great honour. 

Humpback whales like to feed close to shore and enter the local inlets. Around Vancouver Island and along the coast of British Columbia, this made them a welcome food source as the long days of winter passed into Spring.

Humpback whales are rorquals, members of the Balaenopteridae family that includes the blue, fin, Bryde's, sei and minke whales. The rorquals are believed to have diverged from the other families of the suborder Mysticeti during the middle Miocene. While cetaceans were historically thought to have descended from mesonychids— which would place them outside the order Artiodactyla— molecular evidence supports them as a clade of even-toed ungulates — our dear Artiodactyla. Baleen whales split from toothed whales, the Odontoceti, around 34 million years ago.

Monday, 20 January 2020

CETACEANS OF WASHINGTON STATE

Fossil Whale Bone
Oligocene Fossil Whale vertebrae from Majestic Beach, Olympic Peninsula, Washington State, USA.

These lovely water-worn specimens are difficult to ID to species with certainty but they likely hail from an early baleen whale. Found amongst the beach pebbles on the Olympic Peninsula, they are definitely cetacean and very likely baleen as this area is home to some of the earliest baleen whales in the Pacific Northwest.

In 1993, a twenty-seven million-year-old specimen was discovered in deposits nearby that represents a new species of early baleen whale. It is especially interesting as it is from a stage in the group’s evolutionary history when baleen whales transitioned from having teeth to filtering food with baleen bristles. Visiting researcher Carlos Mauricio Peredo studied the fossil whale remains, publishing his research to solidify Sitsqwayk cornishorum (pronounced sits-quake) in the annals of history.

Baby Gray Whale Eschrichtius robustus showing his baleen
The earliest baleen whales clearly had teeth, and clearly still used them. Modern baleen whales have no teeth and have instead evolved baleen plates for filter feeding. I've included a rather good close-up of a baby Gray Whale here that shows the baleen to good effect.

The baleen is the comb-like strainer that sits on the upper jaw of baleen whales and is used to filter food.

We have to ponder when this evolutionary change —moving from teeth to baleen — occurred and what factors might have caused it. Traditionally, we have sought answers about the evolution of baleen whales by turning to two extinct groups: the aetiocetids and the eomysticetids.

The aetiocetids are small baleen whales that still have teeth, but they are very small, and it remains uncertain whether or not they used their teeth. In contrast, the eomysticetids are about the size of an adult Minke Whale and seem to have been much more akin to modern baleen whales; though it’s not certain if they had baleen. Baleen typically does not preserve in the fossil record being soft tissue; generally, only hard tissue, bones & teeth, are fossilized.

Sunday, 19 January 2020

UNLIKELY RHINOCEROS

The Miocene pillow basalts from the Lake Roosevelt National Recreation Area of central Washington hold an unlikely fossil mould of a small rhinoceros, preserved by sheer chance as it's bloated carcass sunk to the bottom of a shallow lake just prior to a volcanic explosion.

We've known about this gem for a long while now. The fossil was discovered by hikers back in 1935 and later cast by the University of California paleontologists in 1948. These were the Dirty Thirties and those living in Washington state were experiencing the Great Depression along with the rest of the country and the world. Franklin D. Roosevelt was President of the United States, navigating the States away from laissez-faire economics. Charmingly, Roosevelt would have his good name honoured by this same park in April of 1946, a few years before researchers at Berkeley would rekindle interest in the site.

Both hiking and fossil collecting was a fine answer to these hard economic times and came with all the delights of discovery with no cost for natural entertainment. And so it was that two fossil enthusiast couples were out looking for petrified wood just south of Dry Falls on Blue Lake in Washington State. While searching the pillow basalt, the Frieles and Peabodys came across a large hole high up in a cave that had the distinctive shape of an upside-down rhinoceros.

This fossil is interesting in all sorts of ways. First, we so rarely see fossils in igneous rocks. As you might suspect, both magma and lava are very hot. Magma, or molten rock, glows a bright red/orange as it simmers at a toasty 700 °C to 1300 °C (or 1300 °F to 2400 °F) in hot chambers beneath the Earth's surface.

During the late Miocene and early Pliocene, repeated basaltic lava floods engulfed about 63,000 square miles of the Pacific Northwest over a period of ten to fifteen million years. After these repeated bathings the residual lava accumulated to more than 6,000 feet.

As the magma pushes up to the surface becoming lava, it cools to a nice deep black. In the case of our rhino friend, this is how this unlikely fellow became a fossil. Instead of vaporizing his remains, the lava cooled relatively quickly preserving his outline as a trace fossil and remarkably, a few of his teeth, jaw and bones. The lava was eventually buried then waters from the Spokane Floods eroded enough of the overburden to reveal the remains once more.

Diceratherium tridactylum (Marsh, 1875)
Diceratherium (Marsh, 1875) is known from over a hundred paleontological occurrences from eighty-seven collections.

While there are likely many more, we've found fossil remains of Diceratherium, an extinct genus of rhinoceros, in the Miocene of Canada in Saskatchewan, China, France, Portugal, Switzerland, and multiple sites in the United States.

He's also been found in the Oligocene of Canada in Saskatchewan, and twenty-five localities in the US, specifically in Arizona, Colorado, Florida, Nebraska, North Dakota, Oregon,  South Dakota, Washington and Wyoming. We know a bit about him. He roamed a much warmer, wetter Washington state some 15 million years ago. By then, the Cascades had arrived and we'd yet to see the volcanic eruptions that would entomb whole forests up near Vantage in the Takama Canyon of Washington state. Diceratherium was a scansorial insectivore with two horns and a fair bit of girth. He was a chunky fellow, weighing in at about one tonne (or 2,200 lbs).

You are welcome to go see his final resting site beside the lake but it is difficult to reach and comes with its own risks. Head to the north end of Blue Lake in Washington. Take a boat and search for openings in the cliff face. You'll know you're in the right place if you see a white "R" a couple hundred feed up inside the cliff. Inside the cave, look for a cache left by those who've explored here before you. Once you find the cache, look straight up. That hole above you is the outline of the rhino.

If you don't relish the thought of basalt caving, you can visit a cast of the rhino at the Burke Museum in Seattle, Washington. They have a great museum and are pretty sporting as they've built the cast hardy enough to let folk climb inside. The Burke Museum recently underwent a rather massive facelift and has re-opened its doors to the public. You can now explore their collections in the New Burke, a 113,000 sq.ft. building at 4300 15th Ave NE, Seattle, WA 98105, United States. Or visit them virtually, at https://www.burkemuseum.org/

Photo: Robert Bruce Horsfall - https://archive.org/details/ahistorylandmam00scotgoog, Public Domain, https://commons.wikimedia.org/w/index.php?curid=12805514

Reference: Prothero, Donald R. (2005). The Evolution of North American Rhinoceroses. Cambridge University Press. p. 228. ISBN 9780521832403.

Reference: O. C. Marsh. 1875. Notice of new Tertiary mammals, IV. American Journal of Science 9(51):239-250

Saturday, 18 January 2020

FOSSIL FAUNAS OF THE PACIFIC NORTHWEST

Some water-worn samples of the fossil bivalve Vertipecten fucanus from Lower Miocene deposits in the Clallam Formation.

These were collected on the foreshore near Clallam Bay, Olympic Peninsula, northwestern Washington. Range zones of pectinid bivalves provide a principal means of age determination and correlation of shallow-water, inshore facies for Washington state. Until Addicott's study from 1976, the area was considered middle Miocene. The new Lower Miocene designation can be credited in large part to the restricted stratigraphic range of Vertipecten fucanus (Dall) and the restricted and overlapping ranges of several other fossil mollusks collected from Alaska to California.

Neogene marine sediments of the West Coast of North America were deposited in a series of widely spaced basins that extended geographically from the western and northern Gulf of Alaska (60°N) to southern California (33°N). Rich molluscan faunas occur extensively throughout these deposits and form the basis for biostratigraphic schemes that are useful for correlating within and between individual basins.

Early biostratigraphic work was concerned with faunas from particular horizons and with the stratigraphic range of diverse taxa, such as Pecten and Turritella, without reference to other fossil groups. Succeeding work increasingly dealt with the relationships of molluscan zones to benthic and, later, planktonic foraminiferal stages. In recent years the age limits of Neogene molluscan stages have become better documented by reference to planktonic microfossils from dated DSDP cores and onshore faunas.

Neogene molluscan faunas from California, the Pacific Northwest states (Oregon and Washington), and southern Alaska have been treated separately due to differences in faunal composition and geographic isolation. As a result, a different biostratigraphic sequence has been described for each region.

Pacific Northwest stages have been formally named and defined, and their names are also used informally for Alaskan faunas. California Neogene stages were proposed early in this century, are in need of redescription, and their usage is informal. Precise correlations between the three regional sequences have not yet been achieved, due to the low number of co-occurring species and the general lack of planktonic microfossils in these largely shallow-water faunas. The objectives of ongoing research include the documentation of the faunas of California and Pacific Northwest stages; formal description of California stages; an improved correlation between regional stage sequences; refinement of age estimates for stage boundaries; and, the establishment of Neogene stages for Alaskan faunas.

Friday, 17 January 2020

PANOPEA ABRUPTA OF CLALLAM

This lovely large fossil bivalve is Panopea abrupta (Conrad) an extinct species of marine mollusc in the family Hiatellidae, subclass Heterodonta.

This specimen was collected from lower Miocene deposits in the Clallam Formation on the foreshore bordering the Strait of Juan de Fuca near Clallam Bay, Olympic Peninsula, northwestern Washington.

Clallam Bay is a sleepy little town on the northwestern edge of the Olympic Peninsula. It was founded back in the 1880s as a steamboat stop and later served as a Mill town. If you are planning to visit the fossil exposures, head to the edge of town where it meets the sea.

Once at the water's edge, head east along the shore until you can go no further. You'll find marine fossils in the sandstone on the shore and cliffs. Mind the tide as access to the fossil site is only possible at low or mid-tide. You'll have to swim for it if you time it poorly. Clallam Bay: 48°15′17″N 124°15′30″W. Near this site, there are many additional fossil localities to explore. In Sequim Bay, you can find Pleistocene vertebrates as well as Miocene cetacean bones near Slip Point. Near the Twin Post Office, you can find Oligocene nautiloids and bivalves (2.5km west in the bluff); You can find crabs including, Branchioplax in the Eocene limestone concretions from Neah Bay.

References: Addicott, Warren. Molluscan paleontology of the lower Miocene Clallam Formation, northwestern Washington, Geological Survey Paper 976.

Thursday, 16 January 2020

EXPLORING THE OLYMPIC PENINSULA

One of the most beautiful in the Pacific Northwest is the Olympic Peninsula from Port Angeles to Neah Bay.

This stretch of coastline is home to the Clallam Formation, a thick, mainly marine sequence of sandstones and siltstones that line the northwestern margin of western Washington. These beachfront exposures offer plentiful fossils for those keen to make the trek.

The beautifully preserved clams, scallops and gastropods found here are mostly shallow-water marine from the late Eocene to Miocene. Time, tide and weather permitting, a site well worth visiting is the south flank of a syncline at Slip Point, near Clallam Bay. Head to the most Northwestern tip of the lower 48, visiting Cape Flattery on the Makah Reservation located 75 miles NW of PA on Hwy 112. Cape Flattery is located approx 7 miles from Neah Bay. The newly constructed wooden walkway takes you to some of the most gorgeous, rugged and wild scenery on the Pacific Coast.

Be sure to take time to explore the internationally known Makah Museum. The museum is open every day during the summer months and closed Mondays and Tuesdays from Sept. 16 through May 31. The hours are 10AM-5PM. The Makah Museum is the nation's sole repository for archaeological discoveries at the Makah Coastal village of Ozette. The centuries-old village was located 15 miles south of present-day Neah Bay. Ozette served the Makah people as a year-around home well into the 20th century.

In 1970, tidal erosion exposed a group of 500-year-old Ozette homes that have been perfectly preserved in an ancient mudslide. The thousands of artifacts subsequently discovered have helped recreate Makahs' rich and exciting history as whalers, fishermen, hunters, gatherers, craftspeople, basket weavers, and warriors. Lake Ozette is located off of Hwy 112 on the Hoko-Ozette Road and follows the road 21 miles to the Ozette Ranger Station.

Three miles of planked trail leads you to Sand Point, one of the most beautiful and primitive beaches on the coast. Continuing north along the beach you will find dozens of Indian petroglyphs at Wedding Rocks, ask for the interpretive handout at the ranger station. The northern point of this 9-mile triangular trail is Cape Alava, with a rocky shore and reefs to explore at low tide. Cape Alava is also the site of an ancient Makah village. The site is now closed and marked with a small sign. Be sure to check a tide table and carry the 10 essentials - and lots of film as seals, deer, eagles and perhaps osprey, otters and whales may be there, rain or shine! Hike north to Cape Alava along the beach to keep the ocean breeze at your back, and avoid Vibram-soled shoes as the cedar plank walkway can be slick!

Salt Creek County Park located on the Strait of Juan de Fuca west of Port Angeles offers fascinating tidal pools, (ask your hosts regarding tide tables). The Dungeness Spit and Wildlife Refuge offers great beach hiking and wildlife. The Olympic Game Farm in Sequim is great for children of all ages. Ediz Hook in Port Angeles provides great views of the Olympic and Cascade mountains. Ediz Hook is part of the 5.5 miles of Waterfront Trail; perfect for jogging, walking, biking, or rollerblading.
The Elwha Valley west of Port Angeles is a beautiful drive along the rushing Elwha River. Madison Falls is an easy hike. Further up the valley beyond Lake Mills is the trailhead to the Olympic Hot Springs.

Port Townsend, known as "Washington's Victorian Seaport" is less than an hour east of Sequim. Victorian homes and commercial buildings erected during the late 1800s are still the city's trademark, along with Fort Worden State Park.

Park fee: A pass is required to enter the Olympic National Park. The fee is $10.00 per carload and is good for 7 days. It can be attained at any of the Park entrances. No pass is required during the winter months for the Elwha Valley or the Sol Duc Valley. Phone # for Olympic National Park Visitors Center in Port Angeles is 360-452-2713.

Getting here…

Directions: From Vancouver, it is a 5-6 hour drive to the Olympic Peninsula. Head South on Oak or Knight to connect up with Hwy 99 to the US border and continue South on Hwy 5, past Bellingham, take Hwy 20 to Anacortes.Head South on Hwy 20 until you get to the Keystone Jetty. Take the ferry from Keystone to Port Townsend. From Port Townsend take Hwy 20 until it connects with Hwy 101. Turn right onto Hwy 101 and head West.

You will pass through Port Angeles. This is an excellent place for you to top up your food stores and fill up with gas. Just after Port Angeles, look for a sign for Hwy 112 (towards Joyce, Neah Bay & Seiqu). Turn right and head West. It is about another 30 km from Port Angeles to Whiskey Creek. From the turn-off, it is about 10 miles to Joyce.

This little town has restaurants and gas stations. From Joyce, it is another 3 miles to the campsite at Whiskey Creek where Joe or Ronee can help direct you to your cabin or campsite.

Wednesday, 15 January 2020

UPTHRUSTING PLATES: WASHINGTON GEOLOGY

Two hundred million years ago, Washington was two large islands, bits of the continent on the move westward, eventually bumping up against the North American continent and calling it home. The shifting continues, subtly changing the landscape like a breath. We only notice when pockets of resistance manifest as earthquakes, some newsworthy, some all but unnoticed. For now, the more extreme movement has subsided laterally and continues vertically, pushing California towards the North Pole. Hello Baja-BC.

The upthrusting of plates move our mountain ranges skyward – the path of least resistance. And it is this dynamic movement that's created the landscape we see today.

The 3,000 meters of the stratigraphic section of the Chuckanut Formation along Chuckanut Drive span an age range of just a few million years. The lower part is late Paleocene with a radiometric age of around 56 million years. The upper part of the section is early Eocene. The fossils found here lived and died very close to where they are now but in a much warmer, wetter, swampy setting. The exposures of the Chuckanut Formation were once part of a vast river delta; imagine, if you will, the bayou country of the Lower Mississippi. The siltstones, sandstones, mudstones and conglomerates of this formation were laid down during a time of luxuriant plant growth in the subtropical flood plain that covered much of the Pacific Northwest.

This ancient wetland provided ideal conditions to preserve the many trees, shrubs and plants that thrived here giving us a lot of information about climate, temperature, the water cycle and humidity of the region. The Chuckanut flora is made up predominantly of plants whose modern relatives live in tropical areas such as Mexico and Central America. While less abundant, evidence of the animals that called this ancient swamp home are also found here. Rare bird, reptile, and mammal tracks have been immortalized in the outcrops of the Chuckanut Formation.

Sumas Eocene Shorebird Trackway
Tracks of a type of archaic mammal of the Orders Pantodonta or Dinocerata (blunt foot herbivores), footprints from a small shorebird, and tracks from an early equid or webbed bird track give evidence to the vertebrates that inhabited the swamps, lakes and riverways of the Pacific Northwest 50 million years ago.

Fossil mammals and bird trackways from Washington State have caused great excitement over the past few years. Many new trackways have been discovered since the 2009 slides near Sumas. George Mustoe and team collected these important finds, bringing them to the Burke Museum in Washington State to study and make available for display.

The movement of these vertebrates was captured in the soft mud on the banks of an ancient river, one of the only depositional environments favourable for track preservation. The terrestrial paleontological record of Washington State at sites like Chuckanut and Racehorse Creek (U-Pb 53 Ma.) is primarily made up of plant material with some wonderfully enticing mammal, shorebird (seen here) and large Diatryma bird tracks on rare occasions.

Monday, 13 January 2020

BREWERICERAS OF HAIDA GWAII

Brewericeras hulenense (Anderson 1938) a fast-moving, nektonic (no idle floating here!) carnivorous ammonite from the Lower Cretaceous (Albian) of Haida Gwaii (Queen Charlotte Islands), British Columbia, Canada.

This specimen is just over 12cm in length, a little under the average of 13.4cm. There are several localities in the islands of Haida Gwaii where Brewericeras can be found (six that I know of and likely plenty more!)

Brewericeras can also be found in Albian deposits in Svedenborgfjellet, Ulladalen, Norway (Cretaceous of Svalbard and Jan Mayen - så fin!) (77.7° N, 15.2° E: paleo-coordinates 66.6° N, 13.6° E) and Matanuska-Susitna County, Alaska, 62.0° N, 147.7° W: paleo-coordinates 57.3° N, 85.6° W (112.6 to 109.0 Ma.)

Sunday, 12 January 2020

JURASSIC COAST BEAUTIES

Charmouth Nodule; Photo and prep: Lizzie Hingley
The talented Lizzie Hingley of Stonebarrow Fossils found this beautiful chock-a-block nodule on Charmouth beach last year.

The nodule contains a couple of Caenisites turneri, along with some Promicroceras and Cymbites ammonites, but there was also a wee surprise just outside the nodule proper. Look closely and you'll see a very well preserved fish!

When she began to prep this nodule, Lizzie had no idea there was going to be a lovely little fish associated with it. Luckily, she caught a glimpse of it when her pen was just millimetres away. The fish is incredibly fragile but looks complete. I'm not sure which species this little fellow is but he shows nice detail in his preservation. A little over fifty fossil fish species are known from the area, including some early teleost fish— a group that includes over 23,000 living species.

The coast and the cliffs around Charmouth and Lyme Regis are famous for their fossils around the world. These are the same beaches that the famous Mary Anning explored as a youngster years ago and Lizzie and many of the locals walk today, all hunting for fabulous Jurassic finds. The most common fossils along the Jurassic coastline in this area are ammonites and belemnites.

Ammonites were predatory, squid-like creatures that lived inside coil-shaped shells. Like other cephalopods, ammonites had sharp, beaklike jaws inside a ring of tentacles that extended from their shells to snare prey such as small fish and crustaceans. We see and collect their beautiful coiled shells but often forget the squid-like fellow who was living inside.

Some ammonites grew more than three feet (one meter) across — tasty snacks for the giant marine reptiles of the day. Most, though not all, ammonites have coiled shells. The chambered part of the shell is called a phragmocone.  It contains a series of progressively layered chambers called camerae, which were divided by thin walls called septae. The last chamber is the body chamber. As the ammonite grew, it added new and larger chambers to the opened end of the shell. A thin living tube called a siphuncle passed through the septa, extending from the body to the empty shell chambers.

Fish detail, Photo: Lizzie Hingley
Beautiful ammonites can be found along the coast at Charmouth and Lyme Regis in southwestern England. Some are in nodules on the beach, brought in as erratics or washed down from the cliffs. Sometimes the tides do all the work and you find the fossils perfectly prepped out, loose in the beach gravels.

Other Jurassic fossils found here include occasional partial or complete marine reptiles — such as Ichthyosaurus and Plesiosaurus. Fossilized fish, as you see here, also pop up on occasion.

As you travel to Charmouth from the east the coastline changes, from the chalk cliffs west of Poole, through the unique rock formations of Lulworth and Durdle Door, to the 28 kilometres (18 miles) and 180 billion pebbles of Chesil Beach and the Fleet Lagoon. The cliffs at West Bay will be particularly familiar to fans of the television series Broadchurch. To the west of Charmouth there is the Lyme Regis ‘ammonite pavement’ on Monmouth beach, with many exposed ammonites in the rocks. And further west you move into the Triassic red cliffs of Devon and the historic pretty coastal villages of Beer and Branscombe.

Photo and fossil preparation: Lizzie Hingley, Stonebarrow Fossils. She has workshops in Dorset and Oxfordshire. Check out more of her work here: https://www.stonebarrowfossils.co.uk/

If you're looking to head to Charmouth, check out the Charmouth Heritage Coast Centre. They also have a well-designed website with the local weather and tide tables.  You can visit it here: https://charmouth.org/chcc/fish/

Saturday, 11 January 2020

PLIENSBACHIAN: APODEROCERAS

This stunning specimen with her regal ridges — and small anomaly — is an Apoderoceras ammonite. Apoderoceras are an extinct genus of cephalopod, an active predatory mollusk belonging to the subclass Ammonoidea.

Apoderoceras is, in fact, a wonderful example of sexual dimorphism within ammonites as the macroconch (putative female) shell grew to diameters in excess of 40 cm – many times larger than the diameters of the microconch (putative male) shell. Apoderoceras has been found in the Lower Jurassic of Argentina, Hungary, Italy, Portugal, and most of North-West and central Europe, including as this one is, the United Kingdom. She was found on the beaches of Charmouth in West Dorset, in South West England, then prepped expertly by the lovely and talented Lizzie Hingley.

Neither Apoderoceras nor Bifericeras donovani are strictly index fossils for the Taylori subzone, the index being Phricodoceras taylori. Note that Bifericeras is typical of the earlier Oxynotum Zone, and ‘Bifericeras’ donovani is doubtfully attributable to the genus.

The International Commission on Stratigraphy (ICS) has assigned the First Appearance Datum of genus Apoderocerasas and of Bifericeras donovani the defining biological marker for the start of the Pliensbachian Stage of the Jurassic, 190.8 ± 1.0 million years ago.  As the brilliant Murray Edmunds points out, this lovely large specimen (macroconch) of Apoderoceras is likely a female. Her larger body perfected for egg production.

Cat's Paw Sutures of Apoderoceras. Simon Guscott Photo
Apoderoceras (Family Coeloceratidae) appears out of nowhere in the basal Pliensbachian and dominates the ammonite faunas of NW Europe. It is superficially similar to the earlier Eteoderoceras (Family Eoderoceratidae, of the Raricostatum Zone), but on closer inspection can be seen to be quite different.  It is, therefore, an invader species and its ancestry is somewhat cryptic.

The Pacific ammonite Andicoeloceras, known from Chile, appears quite closely related and may be ancestral, but the time correlation of Pacific and NW European ammonite faunas is challenging. Even if Andicoeloceras is ancestral to Apoderoceras, no other preceding ammonites attributable to Coeloceratidae are known.

Perhaps there are clues in the Pliensbachian of Canada. We shall have to see. Apoderoceras remains present in NW Europe throughout the Taylori Subzone, showing endemic evolution. It becomes progressively more inflated during this interval of time, the adult ribs more distant, and there is evidence that the diameter of the macroconch evolved to become larger. At the end of the Taylori Subzone, Apoderoceras disappeared as suddenly as it appeared in the region, and ammonite faunas of the remaining Jamesoni Zone are dominated by the Platypleuroceras–Uptonia lineage, generally assigned — but erroneously, IMO!— to the Family Polymorphitidae.

In the NW European Taylori Subzone, Apoderoceras is accompanied — as well as by the Eoderoceratid, B. donovani, which is only documented from the Yorkshire coast, although I know of examples from Northern Ireland — by the oxycones Radstockiceras (quite common) and Oxynoticeras (very rare), the late Schlotheimid, Phricoderoceras (uncommon: note P. taylori is a microconch, and P. lamellosum the macroconch), and the Eoderoceratid, Tetraspidoceras (very rare).

Thank you to Murray Edmunds for his advice and insights on Apoderoceras and the ammonite faunas of the Pacific and NW Europe. You are deeply awesome, my friend! Check out Murray’s Research Gate site for more interesting tidbits.

https://www.researchgate.net/profile/Murray_Edmunds; the photo above of the Cat's Paw Sutures of an Apoderoceras from Dorset are from the lovely Simon Guscott. Look at the wee belemnite that has been washed into the body chamber. Appreciate you!

Friday, 10 January 2020

LOWER ALBIAN AMMONITE

Lovely defined sutures on this rather involute, high-whorled ammonite from the middle part of the Lower Albian in the Mahajanga Province, northwestern Madagascar. This specimen of Phylloceras velledae (Michelin) has a shell with a small umbilicus, arched, acute venter, and at some growth stage, falcoid ribs that spring in pairs from umbilical tubercles, disappearing on the outer whorls.

While this large island off the southeast coast of Africa is known more for exotic lemurs, rainforests & beaches, it also boasts some of the world's loveliest fossils.

This specimen is from a quarry near the top of an escarpment, 3 km to the west of the village of Ambatolafia (coordinates: Lat. 16.330 23.600 S, Long. 46.120 10.20 E). Judging from plate tectonic reconstruction (Stampfli & Borel, 2002), the area was located in middle latitudes within the tropical-subtropical climatic zone at palaeo-latitudes of 40E45.S in the late Early Cretaceous of the early Albian.


Wednesday, 8 January 2020

ARMOURED AGNATHA

This lovely specimen is an armoured agnatha jawless bony fish, Victoraspis longicornualis, from Lower Devonian deposits of Podolia, Ukraine.

Victoraspis longicornualis was named by Anders Carlsson and Henning Bloom back in 2008. The new osteostracan genus and species were described based on material from Rakovets' present-day Ukraine. This new taxon shares characteristics with the two genera Stensiopelta (Denison, 1951) and Zychaspis (Javier, 1985).

Agnatha is a superclass of vertebrates. This fellow looks quite different from our modern Agnatha, which includes lamprey and hagfish. Ironically, hagfish are vertebrates who do not have vertebrae. Sometime in their evolution, they lost them as they adapted to their environment. Photo: Fossilero Fisherman

Ref: Carlsson, A. & Blom, H. Paläont. Z. (2008) 82: 314. https://doi.org/10.1007/BF02988898

Tuesday, 7 January 2020

SUTURES, RIDGES AND LOBES

Ammonitic Suture Detail
Ammonites were predatory, squidlike creatures that lived inside coil-shaped shells.

Like other cephalopods, ammonites had sharp, beak-like jaws inside a ring of squid-like tentacles that extended from their shells. They used these tentacles to snare prey, — plankton, vegetation, fish and crustaceans — similar to the way a squid or octopus hunt today. Catching a fish with your hands is no easy feat, as I'm sure you know. But the ammonites were skilled and successful hunters. They caught their prey while swimming and floating in the water column.

Within their shells, they had a number of chambers, called septa, filled with gas or fluid that were interconnected by a wee air tube. By pushing air in or out, they were able to control their buoyancy in the water column.

They lived in the last chamber of their shells, continuously building new shell material as they grew. As each new chamber was added, the squid-like body of the ammonite would move down to occupy the final outside chamber.

They were a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids — octopuses, squid, and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species.

Ammonites first appeared about 240 million years ago, though they descended from straight-shelled cephalopods called bacrites that date back to the Devonian, about 415 million years ago, and the last species vanished in the Cretaceous–Paleogene extinction event.

Ammonites were prolific breeders that evolved rapidly. If you could cast a fishing line into our ancient seas, it is likely that you would hook an ammonite, not a fish. They were prolific back in the day, living (and sometimes dying) in schools in oceans around the globe.  We find ammonite fossils (and plenty of them) in sedimentary rock from all over the world. In some cases, we find rock beds where we can see evidence of a new species that evolved, lived and died out in such a short time span that we can walk through time, following the course of evolution using ammonites as a window into the past. For this reason, they make excellent index fossils. An index fossil is a species that allows us to link a particular rock formation, layered in time with a particular species or genus found there. Generally, deeper is older, so we use the sedimentary layers rock to match up to specific geologic time periods, rather the way we use tree-rings to date trees.

Ammonites have intricate patterns on their shells called sutures. The different suture patterns tell us what time period the ammonite is from. If they are geometric with numerous undivided lobes and saddles and eight lobes around the conch, we refer to their pattern as goniatitic, a characteristic of Paleozoic ammonites.

If they are ceratitic with lobes that have subdivided tips; giving them a saw-toothed appearance and rounded undivided saddles, they are likely Triassic. If they have lobes and saddles that are fluted, with rounded subdivisions instead of saw-toothed, they are likely Jurassic or Cretaceous.

The Ammonoidea can be divided into six orders:
  • Agoniatitida, Lower Devonian - Middle Devonian
  • Clymeniida, Upper Devonian
  • Goniatitida, Middle Devonian - Upper Permian
  • Prolecanitida, Upper Devonian - Upper Triassic
  • Ceratitida, Upper Permian - Upper Triassic
  • Ammonitida, Lower Jurassic - Upper Cretaceous
In some classifications, these are left as suborders, included in only three orders: Goniatitida, Ceratitida, and Ammonitida. Once you get to know them, ammonites in their various shapes and suturing patterns make it much easier to date a rock formation at a glance.

Their fossil shells are pleasing to the eye, usually taking on a planispiral form— although there are some helically spiralled and fully crazy spiralled forms — known as heteromorphs.

Heteromorphs come in a variety of shapes and sizes. They must have intrigued and mystified those who were first to find them as they do not have an intuitive shape at all for a marine predator.

The beautiful plate you see on the upper left here showing two ammonites is from Sowerby (1837) and is one of the very first scientifically accurate studies of heteromorph ammonites. We see similar species to the heteromorph on the right of the plate in the Nanaimo Group of Vancouver Island, British Columbia.

The beautiful plate to the right shows some of the heteromorph ammonites from Pictet's Paleontology in its second edition (1853-57). Some of the figures are copied from Astier or d'Orbigny works, not included in the first edition.

Ammonite shells have been collected for millennia. During medieval times they were believed to be snakes that had been turned into stone and were sold to people going on pilgrimages. They have been found in archaeological sites in many parts of the world. We find them in archaeological remains spanning human history, across cultures and civilizations.

Ammonites are prized for their scientific and aesthetic value and have been used as building materials, jewellery, amulets, charms to aid in the hunt, religious totems amongst other things. The original discus used by the ancient Greeks in their Olympics was a fossilized ammonite.

A great temple to the god Amon was built at Karnak in Upper Egypt around c. 1785. It is from Amon that we get his cephalopod namesake, the ammonites and also the name origin for the compound ammonia or NH3.


Monday, 6 January 2020

GRAPTOLITES

Graptolites — Graptolita — are colonial animals. The biological affinities of the graptolites have always been debatable. Originally regarded as being related to the hydrozoans, graptolites are now considered to be related to the pterobranchs, a rare group of modern marine animals.

The graptolites are now classed as hemichordates (phylum Hemichordata), a primitive group that probably shares a common ancestry with the vertebrates.

In life, many graptolites appear to have been planktonic, drifting freely on the surface of ancient seas or attached to floating seaweed by means of a slender thread. Some forms of graptolite lived attached to the sea-floor by a root-like base. Graptolite fossils are often found in shales and slates. The deceased planktonic graptolites would sink down to and settle on the seafloor, eventually becoming entombed in the sediment and are thus well preserved.

Graptolite fossils are found flattened along the bedding plane of the rocks in which they occur. They vary in shape, but are most commonly dendritic or branching (such as Dictoyonema), saw-blade like, or "tuning fork" shaped, such as Didymograptus murchisoni.

An excellent resource on graptolites is Old as the Hills. You can find them at:

Sunday, 5 January 2020

GENESIS OF THE ARIETIDAE

Arietidæ plate using heliogravure copper platting
The lovely plate is from the Genesis of the Arietidæ, shared as part of Contributions to Knowledge, 673. pages vii-xi, 1-223; 14 Plates and 35 Woodcuts. Smithsonian, Washington, 1889 by Professor Alpheus Hyatt, an American zoologist and paleontologist.

Hyatt co-founded the American Naturalist, serving as their editor from 1867 to 1870. He became a professor of paleontology and zoology at Massachusetts Institute of Technology in 1870, where he taught for eighteen years, then Professor of Biology and Zoology at Boston University from 1877 until his death in 1902.

Hyatt favoured the use of héliogravure, the technique used here to illustrate some of the best early American ammonite plates. Heliogravure is a type of photogravure or intaglio printmaking or photo-mechanical process whereby a copper plate is grained and then coated with a light-sensitive gelatin tissue exposed to a film positive, then etched.

In France, the correct term for photogravure is héliogravure, while the French term photogravure refers to any photo-based etching technique. The earliest forms of photogravure were developed by two of the original pioneers of photography —  first by Nicéphore Niépce in France in the 1820s, and later Henry Fox Talbot in England.

Niépce was seeking a means to create photographic images on plates that could then be etched and used to make prints on paper with a traditional printing press. Niépce's early images were amongst the first photographs — pre-dating daguerreotypes and the later wet collodion photographic process. Henry Talbot, the inventor of the calotype paper negative process, wanted to make paper prints that would not fade. He worked on his photomechanical process in the 1850s and patented it in 1852 ('photographic engraving') and 1858 ('photoglyphic engraving').

Photogravure in its mature form was developed in 1878 by Czech painter Karel Klíč, who built on Talbot's research. This process, the one still in use today, is called the Talbot-Klič process.

Because of its high quality and richness, photogravure was used for both original fine art prints and for photo-reproduction of works from other media such as paintings. A photogravure is distinguished from rotogravure in that photogravure uses a flat copper plate etched rather deeply and printed by hand, while in rotogravure, as the name implies, a rotary cylinder is only lightly etched, and it is a factory printing process for newspapers, magazines, and packaging.

Many of my favourite paleontological plates were created using this technique. We're fortunate that it allows for both a high degree of detail and multiple printings, ensuring that these beautiful and important early works were not lost in time.

S. S. B. (1890). II.—The Genesis of the Arietidæ. By Professor Alpheus Hyatt. Smithsonian Contributions to Knowledge, 673. 4to. pages vii–xi, 1–223; 14 Plates and 35 Woodcuts. (Washington, 1889.). Geological Magazine, 7(7), 325-326. doi:10.1017/S0016756800186790

Talbot's Correspondence: Biography. De Montfort University.

Saturday, 4 January 2020

BREADBASKET OF EGYPT

Much of Egypt's history is carved in her rock. We think of Egypt as old, with remarkable human history, but the land that formed this part of the world tells us of a much older time in Earth's past.

Egypt, officially the Arab Republic of Egypt, is a country in the northeast corner of Africa, whose territory in the Sinai Peninsula extends beyond the continental boundary with Asia.

Egypt is bordered by the Gaza Strip (Palestinian territories) and Israel to the northeast, the Gulf of Aqaba and the Red Sea to the east, Sudan to the south, Libya to the west, and the Mediterranean Sea to the north. Across the Gulf of Aqaba lies Jordan, across the Red Sea lies Saudi Arabia, and across the Mediterranean Sea lie Greece, Cyprus and Turkey, although none of these share a land border with Egypt.

Five hundred kilometres southwest of Cairo, the flat sabkha plain stretches in all directions covered by a small layer of dark, round pebbles. There are spectacular limestone pillars dotting the landscape of the wonderful karst topography. This land, once the breadbasket of Egypt and the stomping ground of the Pharaohs, is now ruled by pipelines and rusted-out trucks abandoned as wrecks marking the passage of time. Beneath the sand, rust and human history lie some very interesting geology. This rock has been sculpted both through erosion and at the hands of her craftsmen.

The rock here was formed when the Earth's crust was just beginning to cool, 4 to 2.5 billion years ago, during the Archaean. Other rock dates back to the Proterozoic when the Earth's atmosphere was just beginning to form. The oldest of these are found as inliers in Egypt’s Western Desert. The rocks making up the Eastern Desert are largely late Proterozoic in age, the time when bacteria and marine algae were the principal forms of life.

Throughout the country, this older basement is overlain by Palaeozoic sedimentary rocks. Cretaceous outcrops are common. We also find sediments that tell a story of repeated marine transgression and regressions, sea levels rising and falling, characteristic of the Cenozoic. It is from Egypt's Cenozoic geology that we get the limestones used for the great pyramids.

Limestone and Light: Egypt
The pyramids were built of limestone, granite, basalt, gypsum (mortar), and baked mud bricks. Together they form some of the oldest (and last remaining) wonders of the ancient world. The great pyramids of Giza, with their smooth exteriors carved from fine grain white limestone quarried at Tura on the Giza-plateau, are built from Egypt's much older geologic history.

The limestone from Tura was the finest and whitest of all the Egyptian quarries and chosen for the facing stones for the richest tombs. It is interesting in that it is made up almost entirely of Nummulites. Nummulites are the calcareous chambered shells (tests) of extinct forms of marine, amoeba-like organisms (protozoans) called foraminifera that accumulated in huge quantities during the early Cenozoic. Foraminifera are still alive in the sea today, though none quite as large as Nummulites. For the central chamber, with the sarcophagus of the pharaoh, lovely reddish-pink granite from Aswan was used. The granite helped to take the weight of this massive construction.

Back in 2013, archaeologists made an unlikely find in a cave seven hundred kilometres from Giza. Their find, a 4,600-year-old papyrus scroll, details an ancient shipload of rock, likely destined for  Khufu's pyramid. The papyrus is addressed to Ankh-haf, Khufu’s half-brother, and describes the undertaking of an expedition by a 200-man crew to the limestone quarries near Tura, on the eastern shore of the Nile. After loading the blocks onto their ship, the expedition indented to float down the river Nile for a successful delivery.

The Greek historian Herodotus visited Egypt in the 5th century BC, he described the building of Khufu's pyramid by more than 100,000 slaves. Those slaves then had the unenviable task of unloading the 2-3 ton blocks, then pulling them across ramps to be dragged to the construction site.  It is estimated that 5.5 million tonnes of limestone, 8,000 tonnes of granite (imported from Aswan), and 500,000 tonnes of mortar were used in the construction of the Great Pyramid.