of original deposition on an unequal surface, or of subsequent dislocation, appear to promise any plausible solution.[1]
The average height of the cliffs, as far as we could judge by the eye, is 130 or 140 feet; they are traversed in many places by steep ravines running from north to south, and numerous outlying masses of rock shew themselves above the sea at a small distance from low-water mark, a character uniformly presented by the stratified rocks along the whole of the Northern coast.
In some parts the compact grauwacke was wanting for a considerable distance, in such cases the forms which the slate had assumed were rather angular than curvilinear. In the sections of those which have been called saddle-shaped strata, we observed usually that the dip was more precipitous on the western side. In neither variety of the rock could we discover any traces of organic remains, nor could we perceive any imbedded fragments that should indicate their having been formed from the debris of an earlier rock. The strata are traversed by numerous veins of opaque white quartz, but no appearances of any other mineral substances occurred.
The Drawings annexed, (Pl. 33 and 34,) indifferently executed as
- ↑ Professor Jameson (Syst. of Min. vol. 3.) has ascribed these appearances to crystallization. As we are always accustomed to regard terms of science as retaining (where the contrary is not expressly stated) the precise sense in which they have hitherto been uniformly received, the use of this expression is perhaps not strictly correct. The external appearance of these rocks is certainly not that of amass of crystallized matter; and that the phenomenon itself is not invariably connected with the process of crystallization is evident from the consideration that those rocks which are the most highly crystalline in their texture are the most free from these singular configurations. That these appearances, however, may have been effected by a process of Nature, somewhat analogous to crystallization, and depending possibly upon the same remote causes, is perhaps the most satisfactory hypothesis that has hitherto been offered on the subject, and such I apprehend to be the opinion of the school of Werner, though somewhat obscured by the adoption of a term implying identity of operation, in a case where the utmost which can be fairly assumed to exist, appears to be a striking analogy.
