sentences:  Three substantial median moraines extend beneath the waters of Cardigan Bay, parts being exposed at low spring tides as Sarn Badrig, Sarn y Bwlch and Sarn Cynfelin.There are too, swarms of drumlins and a widespread plastering of glacial till elsewhere.The greatest concentration of drumlins is in Denbighshire though there are also distinct areas around the Severn valley.