There are also numerous examples where the crystalline strata dip inward toward the granite ridges, and in this manner form an acute angle with the base, instead of being infolded over and welded to them. The only admissible explanation in these instances of the dip is, that the ends of the strata adjacent to the eruptive masses have sunk into depressions occasioned by the evolution of igneous matter, while their upper edges have been tilted backward. Hence the schists often rise into independent elevated crests all along the chain, and even where no granite appears at the surface. The rocks in Glen-Beg and Glen-Clunie afford examples of this kind, where, as in Cairn-na-well, and the other mountains here, they are highly inclined, and plunge in the direction of the principal range. Geology, viewed in this light, becomes an auxiliary to physical geography, explains many anomalous appearances on the earth’s surface, and successfully accounts for all the flexures, breaks, undulations, and inequalities, that constitute such marked features in the primary strata. Until very recently, the doctrine maintained was, that nearly all the inequalities on the earth’s surface were produced by the erosive and denuding effects of water; that not merely the small lateral valleys and branches of rivers, but likewise all their main trunks, were caused by the slow and gradual working of the stream, cutting the most solid and massive rocks in the same way and almost with the same instrument by which the lapidary divides a block of marble or granite. Nay, with such a ready agent, acting through incalculably remote and indefinite periods of time, the conclusion was arrived at, that “on our continents there is no spot on which a river may not formerly have run.” A sounder philosophy, and one far more accordant with the facts, is now beginning to prevail, namely, that nearly all transverse gorges, by which rivers escape across ridges from one water basin to another, are nothing more than ancient apertures in the crust of the earth, which have resulted from the former disruption and denudation of the rocks: and that rivers, properly so called, have never cut sections through chains, but simply flow in chasms prepared for them.