Hardground with borings

Photograph by Dan Phelps.

Hardground with borings from the Grant Lake Limestone (Upper Ordovician, Maysvillian), Maysville, Kentucky. Mr. Phelps explains, “Hardgrounds are surfaces in the geologic record that lithified on the sea floor and then were bored into and encrusted by marine invertebrates, followed by the deposition of more sediments. They are common in Ordovician carbonates of Kentucky.” And adds, “The creationist explanations for hardgrounds can be hilarious. Especially look at the diagram with gas emissions lifting antediluvian hardgrounds to be redeposited in the Flood.”