Creek Running North

This is part of a crinoid mass mortality layer found on Buffalo Creek in 1996. Becky and Zeke and I dragged the big slab of hardened shale all the way back to California by way of Chicago, Duluth, Rapid City, Moab, Sedona and LA. This rock has gotten around!

Crinoids still survive in some parts of the world — at least those parts that are under seawater. The little cylinders you see here are sections of crinoid stalks, which elevated the feeding structures above the ocean floor, presumably helping to access minor currents more effectively and increasing the edible plankton to inedible silt ratio a bit by getting the feathery feeding arms away from the mud. Not all crinoids were (or are) stalked: “feather stars” are examples of non-stalked living crinoids.

During the middle Devonian, which is when this rock came from, crinoids were important reef-building organisms. This rock may be a section of one of said reeves. I’m not expert enough to tell.