Ch. XIII. THE INCLINED POSITIONS OF STRATA. 285 



It is particularly worthy of remark, that these conglo- 

 merates not only vary in the amount of their dip in different 

 places, but " consist essentially of fragments, more or less 

 rounded, of the nearest primary rocks, but never contain 

 any substance resembling the Caithness schist or sandstone." * 

 It may therefore be presumed that the primary strata were 

 elevated previous to the formation of the conglomerates, since 

 the latter consist of the debris of the former, in consequence 

 of their having been exposed to causes similar to those now 

 in operation ; and if so, then the surface of the primary rocks 

 must have been reduced to a state of inequality, like that 

 which now occurs in analogous districts. For example, we 

 find the existing surface in primary districts variously in- 

 clined, but not corresponding with the dip of their strata; 

 and, in those places where recent deposits occur, these may 

 be arranged parallel to such superficial planes, or they may 

 exhibit inclined concretional layers, superinduced by cohesion, 

 and not coincident with the planes of deposition, as has been 

 already discussed. 



If, on the other hand, we consider the granite of this part 

 of Scotland to have produced the different degrees of eleva- 

 tion exhibited in the adjacent rock, the following suppositions 

 appear to follow from the facts now detailed. The granite, 

 in the first place, must have been in a state of igneous fusion, 

 not only to convert the sedimentary strata into crystalline or 

 primary slates, but to produce the granite- veins, as at Loch 

 Brora and at Cape Wrath ; and then, or subsequently, when 

 consolidated, it elevated these strata. Since that time, the 

 granite must have been elevated at different periods, and 

 under different circumstances, to account for the various 

 appearances ; for sometimes the secondary strata are highly 

 inclined, with a gradual diminution of the angle as they 

 recede from the granite; and, at other times, they are less 

 elevated, and unconformably arranged in the older strata : in 



* Geol. Trans, (New Series), vol. iii. p. 138. 



