Sunday 21 July 2019

INOCERAMUS VANCOUVERENSIS

The late Cretaceous bivalve Inoceramus vancouverensis found in concretion amongst the 72 million year old grey shales of the Northumberland Formation, Campanian to the lower Maastrichtian, part of the upper Cretaceous, from Collishaw Point (Boulder Point to the locals), northwest side of Hornby Island, southwestern British Columbia.

Hornby is a glorious place to collect. The island is beautiful in it's own right and the fossils from here often keep some of their original shell or nacre which makes them quite fetching. Like most of the fossils found at this locality, the specimen was found in concretions rolled smooth by time and tide. The concretions you find on the beach are generally round or oval in shape and are made up of hard, compacted sedimentary rock -- and if you are lucky contain a fossil.

This fellow is found amongst ammonites, baculites and other bivalve fossils. A new species of pterosaur (flying reptile) Gwawinapterus beardi was found on the same beach site and named after Graham Beard, a local collector, author and great friend. I was sharing with "Dinosaur George" Blasting on a podcast today about some of my first trips to Hornby. They were with Graham and his lovely wife, Tina​. I'd split a huge boulder and found one of the most beautiful clustered inoceramus clams with its iridescent nacre intact. The specimen is larger than a dinner plate and had a lovely series of smaller shells nestled inside all Matryoshka-style.

A fun fact about modern or extant bivalves is their life span. Some are among the longest-lived species in the world. In 2007, scientists discovered a species (Arctica islandica) specimen that was between 405 and 410 years old. Apparently you can date clams the way you date trees by counting their ring bands. We've got 160 year old geoducks living in Puget Sound. Giant clams live some 150 years while cold seep clams don't even reach maturity until they are 100 plus. Most species live between three and 10 years with tastier ones having a shorter life span and an affinity for garlic butter. If you're heading to Hornby, you'll want to plan your trip with the ferry schedule and as with most beach sites, the best collecting is during low tide.

If you'd like to check out Dinosaur George's website and link to his podcast, you'll find this link handy: https://dinosaurgeorge.com/ Dino George has a traveling museum with amazing specimens and he's one of the best paleontological educators you'll ever come across. Do check it out as the man is deeply awesome!