Entelophyllum are a type of rugose coral that occurs in groups and form mound shapes in Silurian limestones. You can see that each corallum (tube) is separate from it's neighbor. This is especially obvious when looked at from the top (see detail). Individual calices are relatively small, each generally less than 1 cm across. This specimen is 28 cm in diameter. It was collected by R. Todd Hendricks and donated to the Kentucky Geological Survey.
Eridophyllum is another good example of a rugose (horn) coral that lived in groups or mounds. These fossils are common in the Jeffersonville Limestone (Devonian) The example are from the Falls of the Ohio. The example on the left shows what the mounds look like in the bedrock. The detail on the right, is from another example at the Falls and hows the individual corallums of the group, which look like fingers in the rock matrix. Photographs by R. Todd Hendricks.