This is a large rock with several fossil examples. Featured here is a mold fossil of a brachiopod. I located at least four brachiopod fossils on this rock. The rock measures ~142 mm (5.6 in) long, ~125 mm (4.9 in) wide and ~48 mm(1.90 in) thick. The fossil example pictured measures ~7.5 mm (.29 in) long and ~6.11 mm (.24 in) wide. The fossils all date to the Devonian Period (416-359.2 million years ago). I believe the rock is sandstone.
Rocky bottom of man made lake. Pymatuning Lake. Andover, Ohio, USA
This fossil is one of three total I found on the rock. I am working on posting the others. The extreme close up pictures were taken with a Digital Blue QX5 USB microscope at 10x power.