Before revision: A reef knoll is an immense pile of calcareous material on land that accumulated on the 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 organisms such as sponges to have been free-standing and to withstand the sea currents as material accumulated, and was likely an atoll.
After revision: A reef knoll is an immense pile of calcareous material on land that accumulated on a previously existinga land-based landform that comprises 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 organisms such as sponges to have been free-standing and to withstand the sea currents as material accumulated, and was likely an atoll.