With its distinct, elongated “wings” extending from the hinge line, Weyla looks more like a piece of sculpted jewelry than a clam.
Their ridging is pleasing to the eye as you can see from the big rust and grey fossilized chunky monkey here in my hand.
190 million years ago, these bivalves were a common sight on the seafloor, filtering food from the nutrient-rich waters of the shallow marine basins that once covered what’s now the Nevada desert.
October is my favourite time to explore these sediments. The temperature is just right, not too hot and not too cold. But, be warned. It is also tarantula breeding season so step lively!
Weyla belongs to the family Bakevelliidae, a group of extinct saltwater bivalves that thrived during the Triassic and Jurassic. In Nevada, Weyla fossils are often found in the Sunrise and Gabbs Formations, layers of marine sediment that capture the recovery of life after the great end-Triassic extinction. These ancient beds also yield ammonites, belemnites, crinoids, and early marine reptiles—remnants of a world slowly rebuilding itself into the vibrant Mesozoic ocean ecosystem.
One of the fun things about Weyla is that it’s a bit of a globetrotter. Fossils have been found across Europe, South America, and Asia, making it a useful “index fossil” for correlating Jurassic rocks around the world. Paleontologists use its presence to date marine layers to the Pliensbachian stage, roughly 190 to 185 million years ago.
And here’s a curious twist — Weyla’s flared shape may have helped it stabilize on soft sea floors or even catch gentle currents to reposition itself — a clever adaptation for a sedentary creature. These elegant fossils remind us that even humble clams can leave behind a story of global recovery, resilience, and beauty etched in stone. They are easily recognizable in the field and once you do see a specimen, it is a great indicator that you will find many more fossils in the area.
