TRENT RIVER FOSSIL TURTLE

The Trent River near Courtenay, British Columbia is a hotbed of 85-million-year-old fossil fauna immortalized in stone. 

The bedrock of the Trent River has yielded both marine and terrestrial fossils. 

While you might just gloss over that tidbit of information with a casual nod, consider how unlikely this particular fossil site is. We find fossils of species that lived on the land just metres from those who lived in our ancient oceans — remarkable!

We have found a nearly complete terrestrial helochelydrid turtle, the bones of a juvenile elasmosaur marine reptile and the caudal vertebrae of a Hadrosauroid dinosaur who munched on plants, all within spitting distance of one another.

If you stroll along the Trent solo or as part of a guided tour through the Courtenay Museum, you can walk right up to the Hadrosaur site. It was here many years ago that Mike Trask (whose name may ring a bell as he found the first elasmosaur on the Puntledge River) found bones from a duck-bill dinosaur. Now in Alberta, the province just east of British Columbia, there are areas where if you throw a rock, you'll hit a duck-bill bone, but in British Columbia, they were unheard of. This was not just the first duck-billed dinosaur, it was also the first dinosaur found on Vancouver Island — ever.   

Let's park that little bit of goodness for now and hold your awe and applause for the bounty of the Trent and walk just a wee bit down from the hadrosaur site where you come to the greyish bedrock that looks so plain it seems hardly worth noting, but it was once the resting place of a fossil ratfish, one of the ocean's oddest fish.  

If you head a wee bit upriver, you come to the delineation zone marking the contact between the dark grey marine shales and mudstones of the Haslam Formation where they meet the sandstones of the Comox Formation. 

Fossilized material in the Comox sandstones is less abundant but still well worth a look. If you look closely you begin to see fossilized wood and identifiable fossil plant material. So, hadrosaur, terrestrial, ratfish, marine, then terrestrial plant material. This river just keeps on giving.

Further upstream, there is a small tributary, Idle Creek, where you can find more of this terrestrial material in the sandy shales. A little further up the river, you see more identifiable fossil plants beneath your feet and jungle-like, overgrown snarly trees all around you.

Mesopuzosia sp.; Collection of Rick Ross

If you started your journey at the Trent River Falls and walked west, you pass the infamous Ammonite Alley, where you can find Mesopuzosia sp. and Kitchinites sp. of the Upper Cretaceous (Santonian), Haslam Formation. 

I have included one of the yummy, chocolate coloured Mesopuzosia sp. ammonite found, prepped and photographed by the deeply awesome Rick Ross of the Vancouver Island Palaeontological Society for you to enjoy. 

You are now in the Polytychoceras vancouverense zone. Continuing west, we reach the first of two fossil turtle sites on the river — one terrestrial and one marine. I thought I would share a bit about the terrestrial turtle found here as it is one of my favourite discoveries — after the excitement of the elasmosaur excavated last summer.   

Helochelydrids are a group of poorly known turtles from Late Jurassic to Late Cretaceous deposits in North America and Europe. It is the only known North American member of Helochelydridae.

Naomichelys is known from numerous specimens throughout western North America, most notably the holotype partial shell from the Early Cretaceous Cloverly Formation of Montana and a complete skeleton from the Antlers Formation of Texas. The Cloverly Formation includes a number of vertebrate fossils including a diverse assemblage of dinosaur fossils. the site was designated as a National Natural Landmark by the National Park Service in 1973.

Naomichelys is a member of the family Helochelydridae. We find their fossilized remains in Late Jurassic to Late Cretaceous deposits in North America and Europe. Within North America, only the species Naomichelys speciosa is known from relatively complete material which makes comparisons between specimens from other localities challenging. The delightful Phil Currie along with co-authors Matthew J. Vavrek, Derek W. Larson, Donald B. Brinkman and Courtenay's own Joe Morin described the new species of Helochelydrid terrestrial turtle and put the Trent River near Courtenay, British Columbia on the palaeontological map once again.

The new genus and species of helochelydrid turtle were based on the relatively complete shell from the bedrock of the Trent. This area is a section of the marine Haslam Formation (Santonian) of Vancouver Island, British Columbia, Canada.

The new species is characterized by several distinctive shell features, notably a forward curving process on the anterior portion of the hyoplastra, strongly distinguishing it from N. speciosa. 

The shell is relatively small — and much smaller than one might expect — but does appear to be from a fully grown individual and not a juvenile, suggesting that the species was generally much smaller than other known helochelydrids.

Previously most records of helochelydrids in North America had been assigned to N. speciosa, regardless of actual diagnosable characters. 

The presence of an additional species of helochelydrid from North America tells us that a greater diversity of the taxon was present than was previously recognized. While the interspecific relationships of helochelydrids remain difficult to fully assess, due to the lack of well-preserved specimens, this new species provides additional geographic and phylogenetic data that aids our understanding of this enigmatic group.

As the rock of the Trent River slowly erodes away, it will be interesting to see what it reveals next. We have now found both marine and terrestrial reptiles along with plants, ammonites and other fossil goodies. Tis a story — and river — to keep an eye on!

What to Know Before You Go — Trent River Walk

The full Trent River Walk is 14.8 kilometres of moderate hiking on a well-maintained trail. You may choose to enjoy the wide, flat beginning section of the loop and leave off the narrower sections of the trail where you need to navigate roots and rock. Dogs on leash are welcome. 

You can do this as a family year-round. The trail provides access to the many collecting areas of the river. Be mindful of slippery rocks and keep your eyes peeled for fossils. To enter the trail and find parking, set 375 Hatton Road, Courtenay, British Columbia, into your GPS. Enjoy!