There is a lot of evidence of marine life in the Fort Hays limestone member. This small outcropping contained numerous kinds of fossils as evidenced by the images at left. the first shows a lage number of holes in the rock. I don't know what made these, but suspect that there was some sort of organic inclusion that had eroded out of the boulder. some of the holes showed what looked like the impressions of conical shells.
This image shows bone exposed in one of the cobbles. A more experienced fossil hunter tells me these are probably vertebrea of some marine creature, probably a fish.
This image shows some concretions that are eroding out of the rock. Concretions are formed when organic matter is buried in the silt that later becomes the rock and begins to decay, creating a glue that binds the silt or sand and adheres it to the fossil. The glue in these concretions probably had a lot of iron which accounts for the red coloring.
This is a particularly large concretion that was found sitting on a fallen boulder as shown in the inset. The piece had eroded to the point where it was only necessary to pick the fossil from the rock. The contorted nature of this piece makes it very interesting. All the concretions were similar, though generally much smaller. If I get brave, I may try to remove the rock and discover what caused this. I suspect it was some sort of soft creature.