WANNERIA DUNNAE, EAGER FORMATION

THEROPOD TRACK, TUMBLER RIDGE

Rich McCrea, Dinosaur Track Specialist & Heidi Henderson

Fossil Field Trip to the Dinosaur Fossil beds near Tumbler Ridge.

Here you can see a theropod footprint found by Heidi Henderson, then Chair of the Vancouver Paleontological Society.

Rich McCrae, resident paleontologist and researcher at the site has published many first dinosaur finds from British Columbia. The specimen was donated to the Tumbler Ridge Paleontological Society.

ANKYLOSAUR TRACKWAY

After an exciting hike in the dark through the woods and down a steep incline, we reached the river. The tracks in this photo are from a type of armored dinosaur that date to the very end of the Cretaceous, between 68-66 million years ago.

Imagine a meandering armored tank munching on ferns, shrubs and other low-growing vegetation.

This is a photograph of an ankylosaur trackway filled with water and lit by lamplight along Wolverine River, a research site of Lisa Buckley, one of two magnificent paleontologists working in the area. 

Some of the prints contain skin impressions, which is lucky as many of the prints are so shallow that they can only be recognized by the skin impressions.

There are three types of footprints at the Wolverine River Tracksite - theropods (at least four different sizes) sauropods and ankylosaurs. Filling the prints with water and using light in a clever way was a genius idea for viewing tracks that are all but invisible in bright sunlight by day.

GODT NYTT ÅR

HAPPY 2017!

JOHN DAY FOSSIL BEDS

Oreodont skull, John Day Fossil Beds

More than a 100 groups of mammals and a wide variety of plants have been found in the early Miocene, 39-19 million year old, John Day Formation near Kimberly, Oregon.

The fossiliferous strata that have yielded beautifully preserved specimens of many of the animals we see domesticated today. Dogs, cats, swine and horses are common. Oreodonts, camels, rhinoceros and rodents have also been found in this ancient deciduous forested area.

Here my talented young paleontologist cousin Spencer is holding a well preserved Oreodont skull.Many sites in Oregon yield beautifully preserved fossil shells laid down over 60 million years. The asteroid that hit the Gulf of Mexico at the end of the Cretaceous caused a seafloor rift that split ancient Oregon. The massive hole left behind as the coastal lands slid northward filled in with sediment, refilling the basin.

These marine sediments were uplifted around the time of the birth of Oregon's Coastal Range. Easily collected and identified, as they look very similar to their modern cousins, you can dig for marine fossils all along Oregon's beachfront.

MOSQUE-CATHEDRAL, CORDOBA, SPAIN

A mix of Muslim and Christian architecture can be found in the stunning, and oh so grand Mosque-Cathedral in Cordoba, southern Spain. 

Originally a small temple of Christian Visigoth origin, the Catholic Basilica of Saint Vincent of Lérins has an unusual and collaborative history. 

When Muslims conquered Spain in 711, the church was divided into Muslim and Christian halves.

This sharing arrangement lasted until 784, when the Christian half was purchased by the Emir 'Abd al-Rahman I, who then demolished the original structure to build the grand mosque of Córdoba on its ground.

Córdoba returned to Christian rule in 1236 during the Reconquista, and the building was converted to a Roman Catholic church, culminating in the inclusion of a Renaissance cathedral nave in the 16th century. If you are visiting Andalusia, it is well worth a day trip. Bring your camera and comfortable shoes.

KOTSUIS AND HOHHUG: KWAKWAKWA'WAKA OF THE PACIFIC NORTHWEST

Kotsuis and Hohhug, Nakoaktok

This stunning image of Kotsuis and Hohhug, Nakoaktok — Nakoaktok men in ceremonial dress, with long beaks, crouching on their haunches was taken by Edward Curtis ca. 1914. 

Curtis photographed the Kwakwaka'waka ceremonial dress and masks on the west coast of British Columbia.

The Kwakwa̱ka̱’wakw (or Kwakiutl) are a collective of First Nation groups of the Pacific Northwest Coast. We view them as one people, and they are bound by language, but each had their own Chiefs, beliefs and ancestors. Collectively they cover the territory of British Columbia on northern Vancouver Island, some of the islands around Johnstone Strait and Queen Charlotte Strait and the adjoining mainland. 

United by the common language of Kwak'wala, the broad group can be divided into 13 nations, each with its own clan structure and distinct histories. According to Kwakwaka'wakw folklore their ancestors or ‘na’mima, came to a given spot — by way of land, sea, or underground — in the form of ancestral animals that upon arrival shed their animal appearance and became human.

The first documented contact with Westerners was in 1792 during the expedition led by English officer Captain George Vancouver, and was soon followed by colonies of Europeans settling on Canada's West Coast. 

As was often the way, with settlers came disease and the Kwakwaka’wakw population dropped by up to 75% between 1830 and 1880. Their distinctive ideas about wealth — that status came not from how much you owned but how much you were able to give away — came to the particular attention of the US anthropologist Franz Boas, who wrote extensively on their elaborate gift-giving ceremonies known as the potlach. 

The ceremonial practice was also a particular target of Christian missionaries who saw it as a major obstacle to their "civilizing" mission, and the Canadian government banned the practice in 1885 —although the act was soon amended, proving impossible to enforce.

This photograph of the ceremonial dress and masks of the Kwakwaka'wakw was the creation of American photographer and ethnologist Edward Curtis (1868–1952), famous for his work with First Nations and Native American people. 

Part of a project funded by banking magnate J.P. Morgan, these photographs are from the collection held at the Library of Congress and contain many images not published in Curtis' enormous twenty-volume The North American Indian. In 2015, Taschen produced their epic 768-page The North American Indian: The Complete Portfolios, which gathers Curtis’ entire American Indian portfolio into one publication.

Library of Congress Collection: http://www.loc.gov/pictures/search/?st=grid&co=ecur

SEAGULLS: T'SIK'WI

A gull cries in protest at not getting his share of a meal

Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. 

The Laridae are known from not-yet-published fossil evidence from the Early Oligocene — 30–33 million years ago. 

Three gull-like species were described by Alphonse Milne-Edwards from the early Miocene of Saint-Gérand-le-Puy, France. 

Another fossil gull from the Middle to Late Miocene of Cherry County, Nebraska, USA, has been placed in the prehistoric genus Gaviota. 

These fossil gulls, along with undescribed Early Oligocene fossils are all tentatively assigned to the modern genus Larus. Among those of them that have been confirmed as gulls, Milne-Edwards' "Larus" elegans and "L." totanoides from the Late Oligocene/Early Miocene of southeast France have since been separated in Laricola.

Gulls are most closely related to the terns in the family Sternidae and only distantly related to auks, skimmers and distantly to waders. 

A historical name for gulls is mews, which is cognate with the German möwe, Danish måge, Swedish mås, Dutch meeuw, Norwegian måke/måse and French mouette. We still see mews blended into the lexicon of some regional dialects.

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest and my family, gulls are known as t̕sik̕wi. Most folk refer to gulls from any number of species as seagulls. This name is a local custom and does not exist in the scientific literature for their official naming. Even so, it is highly probable that it was the name you learned for them growing up.

If you have been to a coastal area nearly everywhere on the planet, you have likely encountered gulls. They are the elegantly plumed but rather noisy bunch on any beach. You will recognize them both by their size and colouring. 

Gulls are typically medium to large birds, usually grey or white, often with black markings on the head or wings. They typically have harsh shrill cries and long, yellow, curved bills. Their webbed feet are perfect for navigating the uneven landscape of the foreshore when they take most of their meals. 

Most gulls are ground-nesting carnivores that take live food or scavenge opportunistically, particularly the Larus species. Live food often includes crab, clams (which they pick up, fly high and drop to crack open), fish and small birds. Gulls have unhinging jaws which allow them to consume large prey which they do with gusto. 

Their preference is to generally live along the bountiful coastal regions where they can find food with relative ease. Some prefer to live more inland and all rarely venture far out to sea, except for the kittiwakes. 

The larger species take up to four years to attain full adult plumage, but two years is typical for small gulls. Large white-headed gulls are typically long-lived birds, with a maximum age of 49 years recorded for the herring gull.

Gulls nest in large, densely packed, noisy colonies. They lay two or three speckled eggs in nests composed of vegetation. The young are precocial, born with dark mottled down and mobile upon hatching. Gulls are resourceful, inquisitive, and intelligent, the larger species in particular, demonstrating complex methods of communication and a highly developed social structure. Many gull colonies display mobbing behaviour, attacking and harassing predators and other intruders. 

Certain species have exhibited tool-use behaviour, such as the herring gull, using pieces of bread as bait with which to catch goldfish. Many species of gulls have learned to coexist successfully with humans and have thrived in human habitats. Others rely on kleptoparasitism to get their food. Gulls have been observed preying on live whales, landing on the whale as it surfaces to peck out pieces of flesh. They are keen, clever and always hungry.

HUMMINGBIRD: K'WA'AK'WAMT'A

Irridescent, quick of wing and oh, so beautiful — the wee lovers of nectar who grace our blossoms are hummingbirds.

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, hummingbirds are known as k̕wa̱'ak̕wa̱mt̕a.

TRIASSIC PAPER CLAMS

AMMONITE TIME KEEPERS

Argonauticeras besairei, José Juárez Ruiz

An exceptional example of the fractal building of an ammonite septum, in this clytoceratid Argonauticeras besairei from the awesome José Juárez Ruiz.

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 am 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.

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

Ammonites have intricate and complex patterns on their shells called sutures. The suture patterns differ across species and 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. For some lovely Triassic ammonites, take a look at the specimens that come out of Hallstatt, Austria and from the outcrops in the Humboldt Mountains of Nevada.

Hoplites bennettiana (Sowby, 1826) Christophe Marot

If they have lobes and saddles that are fluted, with rounded subdivisions instead of saw-toothed, they are likely Jurassic or Cretaceous. If you'd like to see a particularly beautiful Lower Jurassic ammonite, take a peek at Apodoceras. Wonderful ridging in that species.

One of my favourite Cretaceous ammonites is the ammonite, Hoplites bennettiana (Sowby, 1826). This beauty is from Albian deposits near Carrière de Courcelles, Villemoyenne, near la région de Troyes (Aube) Champagne in northeastern France.

At the time that this fellow was swimming in our oceans, ankylosaurs were strolling about Mongolia and stomping through the foliage in Utah, Kansas and Texas. Bony fish were swimming over what would become the strata making up Canada, the Czech Republic and Australia. Cartilaginous fish were prowling the western interior seaway of North America and a strange extinct herbivorous mammal, Eobaatar, was snuffling through Mongolia, Spain and England.

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 an ammonite and the rock formation where it is found.

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.

They 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 of rock to match up to specific geologic time periods, rather like the way we use tree rings to date trees. A handy way to compare fossils and date strata across the globe.

References: Inoue, S., Kondo, S. Suture pattern formation in ammonites and the unknown rear mantle structure. Sci Rep 6, 33689 (2016). https://doi.org/10.1038/srep33689

https://www.nature.com/articles/srep33689?fbclid=IwAR1BhBrDqhv8LDjqF60EXdfLR7wPE4zDivwGORTUEgCd2GghD5W7KOfg6Co#citeas

Photos: Argonauticeras besairei from the awesome José Juárez Ruiz.

Photo: Hoplites bennettiana from near Troyes, France. Collection de Christophe Marot

FRANZ BOAS WITH THE HUNT FAMILY, FORT RUPERT 1894

 

DRAGONFLIES: ODONATA

Dragonflies, from the order Odonata, have been around for over 250 million years. The most conspicuous difference in their evolution over time is the steady shrinking of their wingspan from well over two and a half feet down to a few inches.

Voracious predators, today they dine on bees, wasps, butterflies and avoid the attentions of birds and wee lizards -- but back in the day, they had a much larger selection of meals within their grasp.

Time has turned the tables. Small lizards and birds who today choose dragonflies as a tasty snack used to be their preferred prey.

LOWER CRETACEOUS ACANTHOHOPLITES

A very pleasing example of the Ammonite Acanthohoplites bigoureti (Seunes, 1887). Lower Cretaceous, Upper Aptian, from a riverbed concretion, Kurdzhips River, North Caucasus Mountains, Republic of Adygea, Russia. 

Geologically, the Caucasus Mountains belong to a system that extends from southeastern Europe into Asia and is considered a border between them. The Greater Caucasus Mountains are mainly composed of Cretaceous and Jurassic rocks with the Paleozoic and Precambrian rocks in the higher regions. 

Some volcanic formations are found throughout the range. On the other hand, the Lesser Caucasus Mountains are formed predominantly of the Paleogene rocks with a much smaller portion of the Jurassic and Cretaceous rocks. 

The evolution of the Caucasus began from the Late Triassic to the Late Jurassic during the Cimmerian orogeny at the active margin of the Tethys Ocean while the uplift of the Greater Caucasus is dated to the Miocene during the Alpine orogeny.

The Caucasus Mountains formed largely as the result of a tectonic plate collision between the Arabian plate moving northwards with respect to the Eurasian plate. As the Tethys Sea was closed and the Arabian Plate collided with the Iranian Plate and was pushed against it and with the clockwise movement of the Eurasian Plate towards the Iranian Plate and their final collision, the Iranian Plate was pressed against the Eurasian Plate. 

As this happened, the entire rocks that had been deposited in this basin from the Jurassic to the Miocene were folded to form the Greater Caucasus Mountains. This collision also caused the uplift and the Cenozoic volcanic activity in the Lesser Caucasus Mountains.

The preservation of this Russian specimen is outstanding. Acanthohoplites bigoureti are also found in Madagascar, Mozambique, in the Rhone-Alps of France and the Western High Atlas Mountains and near Marrakech in Morocco. This specimen measures 55mm and is in the collection of the deeply awesome Emil Black.

MUSEO NACIONAL DE CIENCIAS NATURALES

HALL OF GIANTS NEW MEXICO

Carlsbad Caverns National Park is in the Chihuahuan Desert of southern New Mexico. 

It features more than 100 caves. The Natural Entrance is a path into the namesake Carlsbad Cavern. Stalactites cling to the roof of the Big Room, a huge underground chamber in the cavern. Walnut Canyon Desert Loop is a drive with desert views. 

Rattlesnake Springs, a desert wetland, attracts reptiles and hundreds of bird species. If you find yourself down in New Mexico it is well worth a visit. 

Definitely bring your camera and some hiking boots with good ankle support and grip for the slippery rock you will need to traverse to explore these beauties in all their glory.

EAGLE SOARING

 

PALEONTOLOGY MUSEUM, FLORENCE, ITALY

CARNOTAURUS SASTREI

Carnotaurus sastrei, a genus of large theropod dinosaur that roamed, Argentina, South America during the Late Cretaceous period, 72 to 69.9 million years ago.

This fellow (or at least his skull) is on display at the Natural History Museum in Madrid, Spain. For now, he is the only known genus of this species of bipedal predator.

The skull is quite unusual. Initially, it has a very marine reptile feel (but make no mistake this guy is clearly a terrestrial theropod). Once you look closer you see his bull-like horns (from whence he gets his name) that imply battle between rivals for the best meal, sexual partner and to be the one who leads the herd.

I'll be interested to see his cousins once more specimens of the genus are unearthed.

DIPLODOCUS CARNEGIEI

Craneo Diplodocus carnegiei, Morrison Formation, Jurassic

OLD HABITS IN CORDOBA SPAIN

Nuns stepping out from the palace, Cordoba, Spain

A group of nuns stepping out in Cordoba, Spain. The nuns earn their living selling sweets and confections using recipes handed down from the Romans and Moors. Many convents are closing because they have fewer nuns so this art may one day be lost.

The procedure for buying the sweets is archaic but charming. You enter the convent into a very small room with a lazy Susan installed on the wall. 

While we did see some nuns in the street, many do not leave the cloister or appear in public. You never see the nun with whom you do the transaction since these are cloistered nuns who avoid direct contact with the public.

On the wall beside the lazy Susan will be a price list. You look it over and decide which sweets you want to buy. Then you ring a buzzer on the wall. After a while, you will hear the voice of a nun greet you and ask you what you want to purchase. 

You share your order and after a few minutes the lazy Susan will turn and you will find your order on it. You then put your money on the lazy Susan and turn it so that the nun can get it. If there is change, the nun puts it on the lazy Susan and you then can get your change.

GRANADA, ANDALUSIA, SPAIN

SHARKS: ELASMOBRANCH FISH

Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven-gill slits on the sides of the head, and pectoral fins that are not fused to the head. 

Modern sharks are classified within the clade Selachimorpha and are the sister group to the rays.

While we often fear them — yes, they can eat you — they should fear us as we dine on them with shocking regularity. In lieu of Shark Fin Soup, a better choice would be investing money and time into their conservation. 

ALHAMBRA PALACE: GRANADA, SPAIN

40 DEGREES OF LATITUDE: THE ROCKIES

Images of darkened valleys, golden late summer light, icy-blue glaciers, white caps on an endless Pacific, small, hardy, yet perfect alpine flowers, spring to mind and each carries a small element but doesn't quite capture it. Heck, even our dog parks are ruggedly beautiful and by the sheer number of visits, would certainly define a large part of my west coast experience.

But the niggling thought is still there. Is there one a single element I could name that epitomizes this vast, diverse landscape? Sea to Sky, lakes to mountains, I've kayaked, hiked, sailed and lovingly explored a great deal of it. Through 40 degrees of latitude, from Yukon to Mexico, the Rocky Mountains are North America's geographic backbone.

This is the Great Continental Divide, where the interminable flatness of the interior collides with the Western Cordillera, a major mountain system of the world. From the highest ridges of the Rockies, the rivers flow to opposite corners of the land, north to the Beaufort Sea, south to the Gulf of Mexico, east to Hudson Bay and west to the Pacific.

KWAS'KWAS: OUR BEAUTIFUL BLUE JAYS

If you live in North American, there is a high probability that you have seen or heard the bird song of the Blue jay, Cyanocitta cristata (Linnaeus, 1758).

Blue Jays are in the family Corvidae — along with crows, ravens, rooks, magpies and jackdaws. They belong to a lineage of birds first seen in the Miocene — 25 million years ago. 

These beautifully plumed, blue, black and white birds can be found across southern Canada down to Florida. The distinctive blue you see in their feathers is a trick of the light. Their pigment, melanin, is actually a rather dull brown. The blue you see is caused by scattering light through modified cells on the surface of the feather as wee barbs.

Blue jays like to dine on nuts, seeds, suet, arthropods and some small vertebrates. 

If you are attempting to lure them to your yard with a bird feeder, they prefer those mounted on trays or posts versus hanging feeders. They will eat most anything you have on offer but sunflower seeds and peanuts are their favourites. 

They have a fondness for acorns and have been credited with helping expand the range of oak trees as the ice melted after the last glacial period.  

Their Binomial name, Cyanocitta cristata means, crested, blue chattering bird. I might have amended that to something less flattering, working in a Latin word or two for shrieks and screams — voce et gemitu or ululo et quiritor. While their plumage is a visual feast, their bird chatter leaves something to be desired. 

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest and my family, a Blue Jay is known as kwa̱skwa̱s. 

The Kwak’wala word for blue is dzasa and cry is ḵ̕was'id. For interest, the word for bird song in Kwak'wala is t̕sa̱sḵwana. Both their songs and cries are quite helpful if you are an animal living nearby and concerned about predators. 

FOSSIL FIELD TRIP VIA JET RANGER

AMMONITES OF THE ARNIOCERAS BEDS

Ammonites (and two gastropods) from the Arnioceras beds near Last Creek in the Canadian Rocky Mountains. The fossils found here are from the Lower Jurassic, Lower Sinemurian, Little Paradise Member of the Last Creek formation. This site is part of the research area for Dr. Howard Tipper, GSC (who is hugely missed) and Dr. Louise Longridge, University of British Columbia.

Several ammonites species can be found here including Arnioceras semicostatum & Arnioceras miserable. The two gastropods you see in the central block have yet to be identified to species. Here's hoping a nice grad student takes an interest. The rare but lovely gastros from this area would make an excellent thesis. Perhaps comparing their distribution to their counterparts in Europe.

CRETACEOUS BONE BEDS

Einiosaurus procurvicornis was a horned dinosaur that roamed North America 74 million years ago. We find their bones in mass bone beds in Cretaceous outcrops of Montana and the Blackfeet Nation. The fossils have been recovered from rich bonebeds, largely consisting of only Einiosaurus fossils. Bonebeds with only one species are called monospecific bonebeds. But why do they occur? ⁣

⁣The most commonly suggested reason is that a herd of animals was suddenly killed by a natural disaster, like a volcanic eruption or flood. 

Their bodies were buried and remained in proximity to each other as they preserved, and today excavations uncover the remains of the unfortunate herd. Multiple other monospecific bonebeds have been found for other species of horned dinosaurs, such as Achelousaurus, causing researchers to suggest some groups of horned dinosaurs did exhibit herding behaviour— and that sometimes they met sudden unfortunate ends. But is sudden mass death from a natural disaster the only reason for monospecific bonebeds? ⁣

⁣Researchers say no. While the monospecific nature is still largely argued to represent herding in many cases, natural disaster is not always the cause of death. Sometimes large numbers of animals die from disease or starvation. Their carcasses could later be pushed together and buried by an event like a mudflow unrelated to their deaths. Their bones could also sit on the surface for years before an event that buries them. ⁣

⁣To understand the cause of a bonebed, researchers look at the bones themselves and the sediment that surrounds them. Bonebeds can tell us a lot about how these animals were living— but there is a lot to be learned from trying to figure out how they died, too. ⁣

Currie, P. J., & Padian, K. (Eds.). (1997). Encyclopedia of dinosaurs. Elsevier. • Rogers, R. R. (1989). Taphonomy of three monospecific dinosaur bone beds in the Late Cretaceous Two Medicine Formation northwestern Montana: Evidence for dinosaur mass mortality related to episodic drought. Graduate Student Theses, Dissertations, & Professional Papers. 5871. • Sampson, S. D. (1995). 

Two new horned dinosaurs from the Upper Cretaceous Two Medicine Formation of Montana; with a phylogenetic analysis of the Centrosaurinae (Ornithischia: Ceratopsidae). Journal of Vertebrate Paleontology, 15(4), 743-760. • Schmitt, J. G., Jackson, F. D., & Hanna, R. R. (2014). Debris flow origin of an unusual late Cretaceous hadrosaur bonebed in the Two Medicine Formation of western Montana. Hadrosaurs. Indiana Press, Bloomington, 486-501.