Saturday 15 July 2023

IDENTIFYING FOSSIL BONE


If you are wondering if you have Fossil Bone, you’ll want to look for the telltale texture on the surface. 

Fossil bone is also heavier than regular bone and will have some heft in your hand. This is because the bone has absorbed the yummy minerals from the material in which it was buried.  

If you plan to have someone help you with identifying your find, it is best to take the specimen outside & photograph it in natural light. Take many photos from every angle. If you have the urge to take a video, move the lens very slowly so that all the wee details can be seen. With fossil bone, you will be able to see the different canals and webbed structure of the bone, sure signs that the object was of biological origin. 

As my good friend Mike Boyd notes, without going into the distinction between dermal bone and endochondral bone — which relates to how they form or ossify — it is worth noting that bones such as the one illustrated here will usually have a layer of smooth (or periosteal) bone on the outer surface and spongy (or trabecular) bone inside.

Dinosaur Bone, Jurassic, Colorado, USA

The distinction can be well seen here in both photographs. The partial weathering away of the smooth external bone has resulted in the exposure of the spongy bone interiors. Geographic context is important, so knowing where it was found is very helpful for an ID. 

Knowing the geologic context of your find can help you to figure out if you've perhaps found a terrestrial or marine fossil. Did you find any other fossils nearby? 

Can you see pieces of fossil shells or remnants of fossil leaves? Things get tricky with erratics. That's when something has deposited a rock or fossil far from the place it originated. We see this with glaciers. The ice can act like a plough, lifting up and pushing a rock to a new location, then melting away to leave something out of context. If you do think you have found fossil bone, it is likely that your local government would like you to report it. You may have found something very significant. I very much hope you have.