Above Coum Mahon How many coums on the Comeraghs? I mentioned the word “com” or “coum” in the last article. So, how many coums are there on the Comeraghs? Now, that`s a good question! Some people say 13, some say 14. In a recent book “Corries, Caves and Coast” by geologists Matthew Parks, Robert Meehan and Sophie Préteseille, the authors claim there are 18 or 19. There`s a big difference between 13 and 18. So which is it? It all comes down to definition, I suppose. How do we define a coum? Many geography textbooks tell us that a coum is an armchair shaped hollow with steep back and side walls gouged into the mountainside by a glacier. It is in essence the birth place of a mountain glacier. The defining characteristics of a bona fide, card carrying coum are: Vertical Cliff Walls: These are found at the back and sides and are created by plucking of the rocks by the ice as gravity encourages it to move downslope. Marshy Hollow sometimes occupied by a lake: Nivation or snow/ice pat