Archive for July 13th, 2012

Quarry work continues on Hiiumaa

July 13th, 2012

KÄINA, ESTONIA–It was a beautiful Baltic day in the Hilliste Quarry on Hiiumaa. Thunderstorms swept by us to the east, but we stayed dry and enjoyed the quickly-changing cloudscape. The Wooster/OSU team was again studying the Hilliste Formation for both its crinoid content and general paleoecology. We did very well.

The typical limestone in the quarry is a biosparite/grainstone as seen above. The most common grains are bits of crinoid stems. The OSU team has found a few crinoid calices and calyx parts, but not as many as you would think given the enormous amount of crinoid skeletal debris in the unit.

It looks like a theme of this year’s Wooster study in the Hilliste Formation may be the sclerobiont (hard substrate-dwelling) fauna, especially the encrusters on corals, stromatoporoids and crinoid stems. Above you see an auloporid coral (the larger tubes connected at their bases) encrusting a favositid coral. Our other encrusters include crinoid holdfasts (three varieties), cornulitids (a kind of worm tube), sheet-like bryozoans, runner-like bryozoans (corynotrypids), and erect bryozoan holdfasts. As far as I know, no one has described a Rhuddanian sclerobiont fauna before.

We have our share of mysteries. Richa picked up the above coiled shell this morning. Bill and I have not seen anything like it in the Silurian before. If these were Jurassic rocks we would have called it a partial ammonite. We know it is not, but we don’t know what it is. A gastropod like Poleumita discors? A nautiloid cephalopod similar to Bickmorites? We’ll have to figure it out later in the lab.

Here is Jonah on the north quarry wall. We dress him brightly every day so we don’t lose him in the Estonian woods.

Richa is in her own world in the western part of the quarry looking for more paleontological treasures.

And finally, our Estonian animal of the day: a spider dutifully guarding her eggs in the quarry floor rubble. I suspect this is the Robust Crab Spider: Xysticus robustus (Hahn, 1832).