Before revision: A reef knoll is a land-based landform that comprises an immense pile of calcareous material that accumulated on a previously existing ancient sea floor.Cope, F. Wolverson (1976) Geology Explained in the Peak District, David & Charles At the time of its accumulation it may have had enough structure from organismssuch as spongesto have been free-standing and to withstand the sea currents as material accumulated, and was likely an atoll.Another possibility is the remains of deep water coral.
After revision: A reef knoll is a land-based landform that comprises an immense pile of calcareous material that had previously accumulated on an ancient sea floor.Cope, F. Wolverson (1976) Geology Explained in the Peak District, David & Charles At the time of its accumulation it may have had enough structure from organismssuch as spongesto have been free-standing and to withstand the sea currents as material accumulated, and was likely an atoll.Another possibility is the remains of deep water coral.