Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/306

 different. It, is also no less inconvenient than unnecessary and improper, that the designation of a granite vein, when on entering a schistose rock it acquires hornblende, should be changed from granite to syenite. This mineral ought to be regarded as accidental, and whether present or absent it makes no alteration in the rock considered as a mass, nor can it alter or affect the validity of any geological reasonings which may be deduced from the relations of the granite in which it is found, to other rocks.

It has with equal want of proof been said that granite of different aspects belonged to different epochas or periods of formation, and we thus read of newer and older granites, as if mineralogists had established criteria by which these several varieties could be referred to a prior or posterior æra. If the connection of trap, sometimes with primary rocks, sometimes with those which contain animal remains, gives a support to these speculations where the rocks of this family are concerned, there are no such connections between granite and the surrounding rocks known as to justify them in this case.

In this place as in many others different varieties of granite are found together, not forming veins nor distinct masses, but graduating into each other by an indistinct transition. The several colours succeed each other at the same time with as little order as do the aspects and proportions of the constituent parts.

The quartz rock appears again to the eastward of Connalach beg, similar in its aspect to that one last named, and after continuing for a few hundred yards, it is succeeded by another variety of granite of a small grain and flesh colour, which forms a large mass of the mountain.

A superficial view of this perpetual repetition of granite and quartz rock, would lead to the false conclusion that these two rocks