DISLOCATIONS OF STRATA. 93 



twenty-eight alternations ; while it is further evident, 

 that the true superposition of the original strata is 

 entirely perverted. The results of these effeets cor- 

 respond to those hereafter described in the case of un- 

 dulations, where the upper points of flexure have 

 been removed. 



That this statement is not visionary, is proved by 

 numerous examples on a small scale ; where not only 

 the fact itself has been clearly ascertained by natural 

 sections, but rendered evident by the peculiar nature 

 of the strata. That it may exist on a very extensive 

 scale also, is rendered highly probable by the facts 

 already noticed respecting the series of Argyllshire ; a 

 tract more fully described in the account of the 

 Western Isles. The whole of this tract may be con- 

 sidered as exceeding twenty miles, on a line taken 

 transversely to the bearings of the strata ; and 

 throughout this space, computing from enumerations 

 taken at different places, there are probably not less 

 than 40,000 strata. Yet the rocks of which they all 

 consist are limited essentially to four, namely, quartz 

 rock, micaceous schist, chlorite schist, and horn- 

 blende schist ; the minor variations being of compa- 

 ratively little moment, and easily conceived to be 

 mere varieties of these four fundamental substances. 

 Throughout this whole space, these strata present an 

 incalculable number of discordant positions, consisting 

 in that frequent alternation of opposite inclinations 

 already described, intermixed with horizontal and 

 vertical beds. It is probably therefore, not un- 

 reasonable to suppose, that this tract consisted once 

 of a series of horizontal strata, of perhaps four sub- 

 stances only ; and that, in consequence of numerous 

 displacements, they have assumed the complicated 

 and deceptive appearance which they now present. 



