Within Britain, the Cairngorm landscape is considered to be of the very highest importance for its glacial geomorphology. It displays a large number and wide range of features associated with glaciation and periglaciation including corries and glacial troughs, moraines, kames, eskers and other depositional features, pro-talus ramparts, meltwater channels. Corrie lakes of glacial origin occur at Loch nan Eun and Lochnagar beneath the mountain of Lochnagar, Loch Brandy and Loch Wharral above Glen Clova, Lochan nan Gabhar beneath Ben Avon and Dubh Lochan beneath Beinn a Bhuird. There are several Lochan Uaine's within the central Cairngorms alongside Loch Etchachan and Loch Coire an Lochain. Loch Kander is another with a glacial origin near the head of Glen Callater. On the eastern margins of the Monadhliath are Lochan a Choire beneath Geal Charn and Loch Dubh. Besides corries, nivation hollows are present such as that at Ciste Mhearaid. Amongst the most significant glacial troughs are those of Loch Avon, Glen Einich, the Lairig Ghru and Strath Nethy within the Cairngorm massif and those of Lock Muick and Glen Clova in the wider Park. Meltwater channels are common, notable examples being those at Chalamain Gap and Eag a' Chait east of the Lairig Ghru, the Ryvoan Pass east of Glenmore and Clais Fhearnaig between Glen Lui and Glen Quoich. The various deposits associated with the Devensian (last) ice age are collectively known as the Caledonia Glacigenic Group and include the Central Grampian and East Grampian Glacigenic subgroups in this area.