Sunday, October 30, 2016

New non-Thalattosaur finds from the Brisbois formation

This summer, as I've already posted, myself, Gloria my daughter and Eric Meitz, a graduate student, went back to the Brisbois formation to get more information for Eric's paper. We did get the needed information. We also hoped to find more "Bernie Blocks' as we call them, containing these wonderful bones. In this, we were disappointed - no more blocks found.

However, I did find something interesting from the same formation. On my way from Portland to Wyoming (to dig dinosaurs at the world-famous Como bluffs) I did excavate a rock plate covered with cephalopod fossils.

The plate was a loose rock, buried just below the soil, broken in four pieces, with one corner showing. It was completely covered with small conical fossils called Rostrums from an extinct squid-like animal.  However, which animal is not clear. 

One type of cephalopod is the Belemnite. Belemnites are found in the Jurassic and the Cretaceous ages, dying out along with 60% of all other life at the end of the Cretaceous. They may have existed back in the Triassic, but have only been found in one formation in China back then (and some paleontologists question this). If these really are Belemnites, this could be a "Really Big Find".

Another type of cephalopod is the Atractite. These animals are found in the Triassic formations, especially in the Triassic Hosselkus limestone of northern California and other formations in Nevada. They date from the same age as the Brisbois (Carnian) and of course are physically close to this formation - only a few hundred miles away. The Atractites are sort of a mixture of Orthoceras (straight Nautilus) and Belemnite (cuttlefish) but in reality they are their own type of animals - the AULACOCERIDA. They existed from the Carboniferous to the Jurassic, 130 million years or so. 

If I was a betting person, I'd bet these are actractites. However we'll probably have to do some sectioning and microscopic examination to say for sure. And we'll have to do some serious work to decide if they are an existing species or a new species. In any event, these certainly are the first fossils of their kind found in Oregon. 

 I intend to take a group back to the site during spring or summer of 2017 to look for the layer they came out of. We'll undoubtedly have to do a cleanup of the loose soil on the slope, like a stratigraphic column, and look at the layers. With work we should be able to find the originating layer and collect some more of the specimens. I also intend to look for more thalattosaur bones as two loose bones were found in the same general area.

Sincerely yours, Greg Carr