26 GBANITE. The same observer also shows that there are certain specialities of structure and composition attached to each of these classes. Thus, under the metamorphic series, he groups the granites of Scandinavia, of the Scottish Highlands (in part), of Donegal, Galway ; and Newry; and under the eruptive series he places the granites of Wicklow, the Mourne mountains, and Dartmoor. Unquestionably this is a classification which will hold good in a general way; and several special districts, such as Galway and Down in Ireland, afford examples of each of these classes of granite in close proximity. At the same time, it is somewhat difficult to define very clearly what we mean by ‘metamor phic ’ as distinguished from ‘ eruptive ’ origin; for, as we may assume that sedimentary rocks, such as grits and slates or shales, when fused by heat under great pressure of superincumbent strata will some times result in the production of granite, it is clear that all granites may be originally in some sense metamorphic rocks. The distinction, however, refers not to the original state and origin of a granitic mass, but to its position in relation to the stratified rocks by which it is bounded or enclosed. If, as in the case of the foliated granite of Galway, it is found to occur merely as a portion of the general mass of sedimentary rocks in which the metamorphic action has been carried out