Meramec River St. Louis mo

[Cjolene]

I think I found this one in a quarry in St. Louis missouri that is about 1/4 of a mile from the Meramec River. I’ve included in picture of the entire rock and two zoomed images. I’m particularly interested in the tiny brown thing. The whole thing is about 3 cm wide X 5 .5 cm long. Thanks for your help!

[ynot]

Sorry, can not tell on this one. The picture is out of focus.