Here is an unidentified semi-spherical colony of stony coral, collected in Post Oak Creek in Sherman, Texas, This is the largest colony that I have found at the site. The colonies range in size from 2.5 cm to 4 cm across. The coralites range from 4 mm to 6 mm across. This specimen has traces of the oyster, (probably Cameleolopha bellaplicata) that it grew on since the muddy Arcadia Park Formation did not provide a suitable hard ground. Other specimens of the coral also all grew on oysters. Trace