Sunday, 19 January 2020
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 rhino.
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. 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 (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. He had two horns on his nose and was a distant relative of our modern rhinoceros. He was also a chunky fellow, weighing in at about one tonne (or 2,200 lbs). You can visit the site, but it is one of the most difficult to reach and comes with significant risk. 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 their 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/
Saturday, 18 January 2020
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.
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
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
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.
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
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|
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.
Tuesday, 14 January 2020
This matrix you see here is the Gault Clay, known locally as the Blue Slipper. This fine muddy clay was deposited 105-110 million years ago during the Lower Cretaceous (Upper and Middle Albian) in a calm, fairly deep-water continental shelf that covered what is now southern England and northern France.
Lack of brackish or freshwater fossils indicates that the gault was laid down in open marine environments away from estuaries. The maximum depth of the Gault is estimated 40-60m a figure which has been reached by the presence of Borings made by specialist Algal-grazing gastropods and supported by a study made by Khan in 1950 using Foraminifera. Estimates of the surface water temperatures in the Gault are between 20-22°c and 17-19°c on the seafloor. These estimates have been reached by bulk analysis of sediments which probably register the sea surface temperature for calcareous nanofossils.
It is responsible for many of the major landslides around Ventnor and Blackgang the Gault is famous for its diverse fossils, mainly from mainland sites such as Folkestone in Kent.
Folkestone, Kent is the type locality for the Gault clay yielding an abundance of ammonites, the same cannot be said for the Isle of Wight Gault, however, the south-east coast of the island has proved to be fossiliferous in a variety of ammonites, in particular, the Genus Hoplites, Paranahoplites and Beudanticeras.
While the Gault is less fossiliferous here on the island it can still produce lovely marine fossils, mainly ammonites and fish remains from these muddy mid-Cretaceous seas. The Gault clay marine fossils include the ammonites (such as Hoplites, Hamites, Euhoplites, Anahoplites, and Dimorphoplites), belemnites (such as Neohibolites), bivalves (notably Birostrina and Pectinucula), gastropods (including the lovely Anchura), solitary corals, fish remains (including shark teeth), scattered crinoid remains, and crustaceans (look for the crab Notopocorystes).
Occasional fragments of fossil wood may also be found. The lovely ammonite you see here is from the Gault Clays of Folkstone. Not all who name her would split the genus Euhoplites. There’s a reasonable argument for viewing this beauty as a very thick form of E. loricatus with Proeuhoplites being a synonym of Euhoplites. Collected, photographed and prepped by Thomas Miller. Approx 35mm across.
Jack Wonfor shared a wealth of information on the Gault and has many lovely examples of the ammonites found here in his collections. If you wish to know more about the Gault clay a publication by the Palaeontological Association called 'Fossils of the Gault clay' by Andrew S. Gale is available in Dinosaur Isle's gift shop.
There is a very good website maintained by Fred Clouter you can look at for reference. It also contains many handy links to some of the best fossil books on the Gault Clay and Folkstone Fossil Beds. Check it out here: http://www.gaultammonite.co.uk/
Monday, 13 January 2020
This specimen is just over 12cm in length, a little under the average of 13.4cm. There are several localities in the Queen Charlotte Islands 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
|Charmouth Nodule; Photo and prep: Lizzie Hingley|
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|
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
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|
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
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.
Thursday, 9 January 2020
The wee candle you see on her forehead is a photophore, a tiny bit of luminous dorsal spine. Many of our sea dwellers have photophores. We see them in glowing around the eyes of some cephalopods. These light organs can be a simple grouping of photogenic cells or more complex with light reflectors, lenses, colour filters able to adjust the intensity or angular distribution of the light they produce. Some species have adapted their photophores to avoid being eaten, in others, it's an invitation to lunch.
In the anglerfish' world, it's dead sexy, an adaptation used to attract prey and mates alike.
Deep in the murky depths of the Atlantic and Antarctic oceans, hopeful female anglerfish light up their sexy lures. When a male latches onto this tasty bit of flesh, he fuses himself totally. He might be one of several potential mates. She's not picky, just hungry. Lure. Feed. Mate. Repeat.
A friend asked if anglerfish mate for life. Well, yes.... yes, indeed they do.
Mating is a tough business down in the depths. Her body absorbs his over time until all that's left are his testes. While unusual, it is only one of many weird and whacky ways our fishy friends communicate, entice, hunt and creatively survive and thrive.
The evolution of fish began about 530 million years ago with the first fish lineages belonged to the Agnatha, a superclass of jawless fish. We still see them in our waters as cyclostomes but have lost the conodonts and ostracoderms to the annals of time. Like all vertebrates, fish have bilateral symmetry; when divided down the middle or central axis, each half is the same. Organisms with bilateral symmetry are generally more agile, making finding a mate, hunting or avoiding being hunted a whole lot easier.
When we envision fish, we generally picture large eyes, gills, a well-developed mouth. The earliest animals that we classify as fish appeared as soft-bodied chordates who lacked a true spine. While they were spineless, they did have notochords, a cartilaginous skeletal rod that gave them more dexterity than the cold-blooded invertebrates who shared those ancient seas and evolved without a backbone. Fish would continue to evolve throughout the Paleozoic, diversifying into a wide range of forms. Several forms of Paleozoic fish developed external armour that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many species, including sharks, became formidable marine predators rather than just the prey of arthropods.
Fishes in general respire using gills, are most often covered with bony scales and propel themselves using fins. There are two main types of fins, median fins and paired fins. The median fins include the caudal fin or tail fin, the dorsal fin, and the anal fin. Now there may be more than one dorsal, and one anal fin in some fishes.
The paired fins include the pectoral fins and the pelvic fins. And these paired fins are connected to, and supported by, pectoral and pelvic girdles, at the shoulder and hip; in the same way, our arms and legs are connected to and supported by, pectoral and pelvic girdles. This arrangement is something we inherited from the ancestors we share with fishes. They are homologous structures.
When we speak of early vertebrates, we're often talking about fishes. Fish is a term we use a lot in our everyday lives but taxonomically it is not all that useful. When we say, 'fish' we generally mean an ectothermic, aquatic vertebrate with gills and fins.
Fortunately, many of our fishy friends have ended up in the fossil record. We may see some of the soft bits from time to time, as in the lovely fossil fish found in concretion in Brazil, but we often see fish skeletons. Vertebrates with hard skeletons had a much better chance of being preserved. In British Columbia, we have lovely two-dimensional Eocene fossil fish well-represented from the Allenby of Princeton and the McAbee Fossil Beds. We have the Tiktaalik roseae, a large freshwater fish, from 375 million-year-old Devonian deposits on Ellesmere Island in Canada's Arctic. Tiktaalik is a wonderfully bizarre creature with a flat, almost reptilian head but also fins, scales and gills. We have other wonders from this time. There are also spectacular antiarch placoderms, Bothriolepsis, found in the Upper Devonian shales of Miguasha in Quebec.
There are fragments of bone-like tissues from as early as the Late Cambrian with the oldest fossils that are truly recognizable as fishes come from the Middle Ordovician from North America, South America and Australia. At the time, South America and Australia were part of a supercontinent called Gondwana. North America was part of another supercontinent called Laurentia and the two were separated by deep oceans.
These two supercontinents and others that were also present were partially covered by shallow equatorial seas and the continents themselves were barren and rocky. Land plants didn't evolve until later in the Silurian Period. In these shallow equatorial seas, a large diverse and widespread group of armoured, jawless fishes evolved: the Pteraspidomorphi. The first of our three groups of ostracoderms. The Pteraspidomorphi are divided into three major groups: the Astraspida, Arandaspida and the Heterostraci.
The oldest and most primitive pteraspidomorphs were the Astraspida and the Arandaspida. You'll notice that all three of these 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.
Wednesday, 8 January 2020
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 include 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
|Ammonitic Suture Detail|
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.
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.
Ammonite shells have been collected by people 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, jewelry, 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
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.
Sunday, 5 January 2020
|Arietidæ plate using heliogravure copper platting|
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
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 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.
Friday, 3 January 2020
|Florissantia sp., from the Allenby Formation, Princeton, BC|
The early angiosperms developed advantages over contemporary groups — rapid reproductive cycles — which made them highly efficient, adapting well to "weedy" growth. These modifications, including flowers for the attraction of insect pollinators, proved advantageous in many habitats.
Interaction between plant and pollinator has been a driving force behind the astounding diversification of both flowering plants and insects.
Some of the earliest known flowering plants are found in northeastern British Columbia coalfields. Late Cretaceous (about 101–66 million years ago) floras of the Dawson Creek area of British Columbia, and Milk River, Alberta, reveal increasing dominance by angiosperms. These fossils, while generally resembling some living angiosperms, represent old, extinct families, and their relationships to living groups remain unclear.
At the end of the Cretaceous, the climate cooled, inland seas covering much of western Canada drained, and dinosaurs became extinct. At the boundary between the Cretaceous and Paleogene is evidence of extinction amongst land plants, too. During this interval of mass extinction, the Earth was struck by a massive meteorite. The fallout from this impact is preserved in boundary sediments in southern Saskatchewan as a pale clay, rich in rare earth elements such as iridium.
In the early Paleogene period (66–56 million years ago), we entered the age of mammals. Paralleling the rise of mammals is the rise of modern flora, which consists overwhelmingly of flowering plants.
Early Paleogene fossils are found over much of Alberta — Red Deer River, Lake Wabamun coalfields and Robb to Coal Valley coalfields — and southern Saskatchewan — Eastend area to Estevan coalfield — to as far north as Ellesmere Island. These floras reveal a variety of flowering plants, including members of the sycamore, birch and walnut families, but the most abundant fossil plants are the katsuras and the dawn redwood, now native only to southeastern Asia.
In the mid-Paleogene period (56–34 million years ago) brief climatic warming coincided with the rapid diversification of flowering plants. Eocene fossils in British Columbia (Princeton, Kamloops and Smithers areas) reveal increasing numbers of modern plant families, with extinct species of birch, maple, beech, willow, chestnut, pine and fir.
Exceptionally well-preserved fossil forests found on Axel Heiberg and Ellesmere islands in the Canadian Arctic illustrate clearly the contrast between modern Canadian vegetation and the floras of a much warmer past. These fossil forests, 40 to 60 million years old, consist of large stumps, many over 1 m in diameter, preserved where they grew, still rooted in ancient soil.
Thick mats of leaf litter that formed the forest floor reveal the types of plants inhabiting the forests. Lush redwood and cypress swamps covered the lowlands, while the surrounding uplands were dominated by a mixed conifer and hardwood forest resembling that of modern eastern North America. Even accounting for continental drift, these forests grew well above the Arctic Circle, and bear witness to a time in Canada's past when a cold arctic climatic regime did not exist.
Around 45-50 million years ago, during the middle Eocene, a number of freshwater lakes appeared in an arc extending from Smithers in northern British Columbia, south through the modern Cariboo, to Kamloops, the Nicola Valley, Princeton and finally, Republic, Washington.
The lakes likely formed after a period of faulting created depressions in the ground, producing a number of basins or grabens into which water collected — imagine gorgeous smallish lakes similar to Cultus Lake near Chilliwack, British Columbia.
|Fossilized wood permineralized in fine-grained sediment|
The ash washed into the lakes and because of its texture, and possibly because of low water oxygen levels on the bottoms that slowed decay beautifully preserved the dead remains of plant, invertebrate, and fish fossils — some in wonderful detail with fascinating and well-preserved flora.
Near the town of Princeton, British Columbia, we see the results of that fine ash in the many fossil exposures. The fossils you find here are Middle Eocene, Allenby Formation with a high degree of detail in their preservation. Here we find fossil maple, alder, fir, pine, dawn redwood and ginkgo material. The Allenby Formation of the Princeton Group is regarded as Middle Eocene based on palynology (Rouse and Srivastava, 1970), mammals (Russell, 1935; Gazin, 1953); freshwater fishes (Wilson, 1977, 1982) and potassium-argon dating (Hills and Baadsgaard, 1967).
Several species of fossilized insects can be found in the area and rare, occasional fossil flowers and small, perfectly preserved fish. More than 50 flowers have been reported (Basinger, 1976) from the Princeton chert locality that crops out on the east side of the Similkameen River about 8 km south of Princeton, British Columbia.
The ﬁrst descriptions of fossil plants from British Columbia were published in 1870–1920 by J.W. Dawson, G.M. Dawson, and D.P. Penhallow. Permineralized plants were ﬁrst described from the Princeton chert in the 1970s by C.N. Miller, J.F. Basinger, and others, followed by R.A. Stockey and her students. W.C. Wehr and K.R. Johnson revitalized the study of fossils at Republic with the discovery of a diverse assemblage in 1977.
In 1987, J.A. Wolfe and Wehr produced a United States Geological Survey monograph on Republic, and Wehr cofounded the Stonerose Interpretive Center as a venue for public collecting. Systematic studies of the Okanagan Highlands plants, as well as paleoecological and paleoclimate reconstructions from palynomorphs and leaf ﬂoras, continue to expand our understanding of this important Early Eocene assemblage.
One of the sister sites to McAbee, the Driftwood Canyon Provincial Park Fossil Beds, offers an honours system for their site. Visitors may handle and view fossils but are asked to not take them home. Both Driftwood Canyon and McAbee are part of that arc of Eocene lakebed sites that extend from Smithers in the north, down to the fossil site of Republic Washington, in the south. The grouping includes the fossil sites of Driftwood Canyon, Quilchena, Allenby, Tranquille, McAbee, Princeton and Republic. Each of these localities provides important clues to our ancient climate.
|Eocene Plant Fauna / Eohiodon Fish Fossil / McAbee|
The fossils are preserved here as impressions and carbonaceous films. We see gymnosperm (16 species); a variety of conifers (14 species to my knowledge); two species of ginkgo, a large variety of angiosperm (67 species); a variety of insects and fish remains, the rare feather and a boatload of mashed deciduous material. Nuts and cupules are also found from the dicotyledonous Fagus and Ulmus and members of the Betulaceae, including Betula and Alnus.
We see many species that look very similar to those growing in the Pacific Northwest today. Specifically, cypress, dawn redwood, fir, spruce, pine, larch, hemlock, alder, birch, dogwood, beech, sassafras, cottonwood, maple, elm and grape. If we look at the pollen data, we see over a hundred highly probable species from the site. Though rare, McAbee has also produced spiders, birds (and lovely individual feathers) along with multiple specimens of the freshwater crayfish, Aenigmastacus crandalli.
For insects, we see dragonflies, damselflies, cockroaches, termites, earwigs, aphids, leafhoppers, spittlebugs, lacewings, a variety of beetles, gnats, ants, hornets, stick insects, water striders, weevils, wasps and March flies. The insects are particularly well-preserved. Missing are the tropical Sabal (palm), seen at Princeton.
200 km to the south, fossil leaves and ﬁsh were ﬁrst recognized at Republic, Washington, by miners in the early 1900s. We find the impressive Ensete (banana) and Zamiaceae (cycad) at Eocene sites in Republic and Chuckanut, Washington. Many early workers considered these ﬂoras to be of Oligocene or Miocene age. C.A. Arnold described Canadian occurrences of conifers and Azolla in the 1950s. Palynological studies in the 1960s by L.V. Hills, G.E.Rouse, and others and those of fossil ﬁsh by M.V.H. Wilson in the 1970–1980s provided the framework for paleobotanical research at several key localities.
With the succession of ice ages that swept down across North America in the Pleistocene, there were four intervening warm periods. These warmer periods help many species, including the genus Oenothera, enjoy four separate waves of colonization — each hybridizing with the survivors of previous waves. This formed the present-day subsection Euoenothera. The group is genetically and morphologically diverse and contains some of the most interesting of the angiosperms.
Today, there are about 145 species of herbaceous flowering plants in the genus Oenothera, all native to the Americas. It is the type genus of the family Onagraceae. We know them by many names — evening primrose, suncups, and sundrops — but they are not closely related to the true primroses (genus Primula).
Oenothera flowers are pollinated by insects, such as moths and bees. One of the most interesting things I've learned (thank you, Jim Barkley) is a clever little evolutionary trait exhibited by the beach evening primrose, Oenothera drummondil. These lovelies can actively sense and respond to the buzzing of bees. Marine Veits et al. were able to show that this species has evolved to respond to the sound of bees by producing nectar with a higher sugar concentration, certainly yummy by bee standards — therein attracting more pollinators and increasing the plant species reproductive success.
David R. Greenwood, Kathleen B. Pigg, James F. Basinger, and Melanie L. DeVore: A review of paleobotanical studies of the Early Eocene Okanagan (Okanogan) Highlands floras of British Columbia, Canada, and Washington, USA.
Sauquet H, von Balthazar M, Magallón S, et al. The ancestral flower of angiosperms and its early diversification. Nat Commun. 2017;8:16047. Published 2017 Aug 1. doi:10.1038/ncomms16047
Marine Veits Itzhak Khait Uri Obolski, et al. Flowers respond to pollinator sound within minutes by increasing nectar sugar concentration. https://doi.org/10.1111/ele.13331
Photo: Pictured above is a beautiful example of Florissantia sp., an extinct species of angiosperm from Eocene outcrops near Princeton, British Columbia. It is one of the best-preserved specimens I've seen from the Allenby. Florissantia can be found in western North America outcrops dating from the Eocene to the Oligocene, 56 to 23 million years ago.
Thursday, 2 January 2020
Many are marine, but two-thirds of all living species live in freshwater or on land. Their entry into the fossil record goes all the way back to the Cambrian.
Slugs and snails, abalones, limpets, cowries, conches, top shells, whelks, and sea slugs are all gastropods. They are the second-largest class of animals with over 60,000–75,000 known living species. The two beauties you see here are Turritella, a genus of medium-sized sea snails with an operculum, marine gastropod mollusks in the family Turritellidae. They hail from the Paris Basin and have tightly coiled shells, whose overall shape is basically that of an elongated cone. The name Turritella comes from the Latin word turritus meaning "turreted" or "towered" and the diminutive suffix -ella.
Many years ago, I had the pleasure of collecting in the Paris Basin with a fellow named Michael. I had stalked the poor man from Sunday market to Sunday market, eventually meeting up with him in the town of Gordes. He graciously shared his knowledge of the local fossil localities from the hills south of Calais to Poitiers and from Caen to the Rhine Valley, east of Saarbrücken. I deeply regret losing my notebook from that trip but cherish the fossils and memories.
The Paris Basin has many fine specimens of gastropods. These molluscs were originally sea-floor predators, though they have evolved to live happily in many other habitats. Many lines living today evolved in the Mesozoic. The first gastropods were exclusively marine and appeared in the Upper Cambrian (Chippewaella, Strepsodiscus). By the Ordovician, gastropods were a varied group present in a variety of aquatic habitats. Commonly, fossil gastropods from the rocks of the early Palaeozoic era are too poorly preserved for accurate identification. Still, the Silurian genus Poleumita contains fifteen identified species.
Most of the gastropods of the Palaeozoic belong to primitive groups, a few of which still survive today. By the Carboniferous, many of the shapes we see in living gastropods can be matched in the fossil record, but despite these similarities in appearance the majority of these older forms are not directly related to living forms. It was during the Mesozoic era that the ancestors of many of the living gastropods evolved.
In rocks of the Mesozoic era, gastropods are more common as fossils and their shells often very well preserved. While not all gastropods have shells, the ones that do fossilize more easily and consequently, we know a lot more about them. We find them in fossil beds from both freshwater and marine environments, in ancient building materials and as modern guests of our gardens.
Wednesday, 1 January 2020
|Johnny Scow's Kwakwaka'wakw Kwakiutl House, 1918|
The day-to-day activities of each of these communities would much like our own. Babies were born, meals were served and life followed a natural cycle. As coastal societies lived their lives they also left their mark. Sometimes through totems and carvings but almost always through discarded shells and scraps of bone from their food.
These refuse heaps contain a wealth of information about how that community lived, what they ate and what environmental conditions looked like over time. They also provide insight into the local gastronomic record on diet, species diversity, availability and variation.
This physical history provides a wonderful resource for archaeologists in search of botanical material, artifacts, broken cooking implements and my personal favourite, mollusc shells. Especially those formed from enormous mounds of bivalves and clams. We call these middens. Left for a period of time, these unwanted dinner scraps transform through a process of preservation.
Shell middens are found in coastal or lakeshore zones all over the world. Consisting mostly of mollusc shells, they are interpreted as being the waste products of meals eaten by nomadic groups or hunting parties. Some are small examples relating to meals had by a handful of individuals, others are many metres in length and width and represent centuries of shell deposition. In Brazil, they are known as sambaquis, left between the 6th millennium BCE and the beginning of European colonization.
Younger shell middens are found in Latvia (associated with Comb Ware ceramics), Sweden (associated with Pitted Ware ceramics), the Netherlands (associated with Corded Ware ceramics) and Schleswig-Holstein (Late Neolithic and Iron Age). All these are examples where communities practised a mixed farming and hunting/gathering economy.
On Canada's west coast, there are shell middens that run for more than 1 kilometre (0.62 mi) along the coast and are several meters deep. The midden in Namu, British Columbia is over 9 metres (30 ft) deep and spans over 10,000 years of continuous occupation.
Shell middens created in coastal regions of Australia by Indigenous Australians exist in Australia today. Middens provide evidence of prior occupation and are generally protected from mining and other developments. One must exercise caution in deciding whether one is examining a midden or a beach mound. There are good examples on the Freycinet Peninsula in Tasmania where wave action currently is combining charcoal from forest fire debris with a mix of shells into masses that storms deposit above high-water mark.
Shell mounds near Weipa in far north Queensland are claimed to be middens but are actually shell cheniers, beach ridges re-worked by nest mound-building birds. The midden below is from Santa Cruz, Argentina. We can thank Mikel Zubimendi for the photo.
The Danish use the term køkkenmøddinger, coined by Japetus Steenstrup, a Danish zoologist and biologist, to describe shell heaps and continues to be used by some researchers.
So what about these ancient shells is so intriguing? Well, many things, not the least being their ability to preserve the past. Shells have a high calcium carbonate content.
Calcium carbonate is one of my favourite chemical compounds. It is commonly found in rocks — as the minerals calcite and aragonite, most notably as limestone, which is a type of sedimentary rock consisting mainly of calcite — and is the main component of pearls, snails, eggs and the shells of marine organisms. About 4% of the Earth's crust is made from calcium carbonate. It forms beautiful marbles and the 70 million-year-old White Cliffs of Dover — calcium carbonate as chalk made from the skeletons of ancient algae.
Time and pressure leach the calcium carbonate, CaCO3, from the surrounding marine shells and help embalm bone and antler artifacts that would otherwise decay. Much of what we know around the modification of natural objects into tools comes from this preservation. The calcium carbonate (CaCO3) in the discarded shells tends to make the middens alkaline, slowing the normal rate of decay caused by soil acidity and leaving a relatively high proportion of organic material — food remnants, organic tools, clothing, human remains — to sift through and study.
Calcium carbonate shares the typical properties of other carbonates. In prepping fossil specimens embedded in limestone, it is useful to know that limestone, itself a carbonate sedimentary rock, reacts with stronger acids. If you paint the specimen with hydrochloric acid, you'll hear a little fizzling sound as the limestone melts and carbon dioxide is released: CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l). I tend to use a 3-5 molar solution, then rinse with plain water.
Calcium carbonate reacts with water saturated with carbon dioxide to form the soluble calcium bicarbonate. Bone already contains calcium carbonate, as well as calcium phosphate, Ca2, but it is also made of protein, cells and living tissue. Decaying bone acts as a sort of natural sponge that wicks in the calcium carbonate displaced from the shells. As protein decays inside the bone, it is replaced by the incoming calcium carbonate, making the bone harder and more durable.
The shells, beautiful in their own right, make the surrounding soil more alkaline, helping to preserve the bone and turn dinner scraps into exquisite scientific specimens for future generations.