BOG (from Ir. and Gael. bogach, bog, soft), soft, spongy, water-logged ground, composed of vegetation, chiefly mosses, in various stages of decomposition forming "peat" (q.v.). With very heavy rain there is danger of a "bog-slide," or "bog-burst," which may obliterate the neighbouring cultivated land with a deposit of the contents of the bog. Destructive bog-slides have occurred in Ireland, such as that at Kilmore, Co. Galway, in igiog, but on a smaller scale they have been ex-perienced in several parts of the British Isles.