Spent overnight at the Bois Blanc Formation site with a great field comrade. The focus this time was less on the arenaceous hardground, and more on the hummocky material. Although, to be fair, we were fairly systematic in our sweep. Overall, we made out pretty well, and on at least one register, pretty damn amazing. So, on to the report...
This shows the big difference between the two lithologies. On the left is a giant rugose coral in the hummocky material, and on the right is a tabulate on the arenaceous hardground.
I don't get into the habit of picking up corals, but these were small and interesting enough to find their way into my pocket.
Calymene platys occur occasionally in this material, and usually their only announcement is as an outline on the edge of the rock. In most cases, if you can see the outline, it means much of it is already worn away. The specimen at the bottom does continue into the rock, so there is hope it may be complete, even if there is almost no way of preserving that flaky shell in the process. This material can be tough and sticky at the same time.
A small Burtonops cristata that appears to be complete. I've put it under the scribe briefly, and I haven't got as far to see if the pygidium is there, but the remainder of the thorax appears to be.
And now for what was truly exciting, but may not appear so thrilling in photos. We encountered material where there seemed to be a concentration of Terataspis grandis fragments, suggestive of a moulting ground or tidal sorting. Some rocks were so filled with fragments that it was like they were just layered right on top of each other. Nothing complete, but some good parts, including a glabella.
To most people, these would just look like a big bunch of rocks with a few blackish bits, but throughout and buried in the matrix are the telltale pustular signs of the giant lichid. It will require a good deal of time and patience in the prep lab to get this up to par. The shell is flaky, but there are intervals where they are quite robust and inflated in the matrix. The evidence of them was so ridiculously abundant that we only took the best pieces home. Not many trilobite collectors can say they even have the tiniest fragment of this species, and so we were definitely spoiled. I'll post an update once I can spend some quality time in the lab with these.
UPDATE: Just a preliminary abrasion on this piece, before and after. I'm thinking this is a ventral cranidium (maybe... I have no idea). Other pieces I sampled... wow... They seem to just go on and on in the rock, which means I could get some very nice pieces once all is said and done.
And a few more works in progress: