Search the Community

Hi all- They don't call it Good Friday for nothing. The Sundance Fm is something I have wanted to explore on my own for a while and I finally got the chance to do a little exploring in this Jurassic Ocean of Wyoming last Friday. I went to a new (-ish ranch). My girlfreind and I went to this place two years ago on Easter and found dinosaurs in the Morrison Fm. Nothing worth collecting but there they were. This this time I went to explore the beds below the Morrison. The first outcrop I got to was a little outcrop of a layer that I have seen many times before... it is loaded with star shaped crinoid stem pieces... Pentacrinites. I have a bunch of these already, but I always collect a sample when I find the layer. I also know that there are rare occurences of other echinoderms in this layer. I found some sea urchin spines. Then off to the main hillside. At the base of the hillside I found the same layer exposed, but much more extensively and I started hunting for the more elusive echinoderms. And it worked... I found a crinoid head with a bit of stalk. And the remains of a starfish. As far as I know there are only two complete starfishes from this layer known from Wyoming, both in private collections. Even parts and pieces are rare. Here is the crinoid.... the calyx is at the bottom and slightly eroded; one feather arm is quite visible. Above the calyx is a piece of the stem, with cirri visible. Pentacrinites is known for its cirri... little 'branches' that come off of the 'stem'. This will never be a superb crinoid specimen like we have seen from other folk. The echinoderms from this layer do not prep well at all... you get what you get. Still this is my very first crinoid calyx. Yee haa. And the starfish is only three busted arms. Excellent finds for one day. Now I was off to upper layers... uphill in search of ichthyosaur bones. The Sundance is often littered with belemnites, and this slope was not any different. Lots of belemnites. Then I found this chunk of rock. At the very top of the Sundance is a platy sandstone layer that has nice pterosaur tracks. But these are only found south of Casper, so I was not expecting to see this at all. I was not even close to the top of the Sundance, and well north of Casper. But I am interpreting this as a lousy pterosaur footprint (Pteraichnus) and two 'hand'prints. Now, I do claim to be quite skeptical of uncertain traces such as these, but if you sompare these with nice pterosaur tracks, they are quite similar, but less defined, so an undertrace or an infilling. The second problem with this is that the handprints are going the opposite direction than the footprint... Here are some better tracks from my friend Susan B's blog. You decide. I found no others in the area. I walked up and down this hill until... bones in concretion!!! Then more... pieces of concretion on the slope with bones in them. I spent an hour collecting as many as possible and found a few that fit together. I decided they were part of an icthyosaur snout. No teeth to be found, but I am told their teeth fallout pretty easily postmortem. Here is the scene with my backpack for scale. The rock to the left of my pack has a couple of pieces of ichthy snout on it... shown in the second photo. This was a good day indeed. At home I washed the pieces of concretion and did a bit of puzzle work. Here is my cat, Misha, supervising the drying of an ichthyosaur. There is about 15 inches of snout pieces that fit together. The pieces in the foreground fit together too, but I do not know what they are. And my take of belemnites and a few clams. Good Friday was a good day after indeed. I will return to this site after a few good rains a try to find the source of this concretion. jpc