262 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [Feb. 5, 



not have had its surface affected by them in a correspondingly pre- 

 dominant degree. Even as regards the Lowlands, I am suspicions, 

 I confess, as to the influence which a preconceived theory has had 

 on the estimate of evidence which appears to be so nicely balanced. 

 But in any case the argument from analogy, as between the Lowlands 

 and the Highlands, is one on which no reliance can be placed. 



I have quoted in a former page the general description, given by 

 Mr. Geikie, of the Highland strata, as waved and crumpled and 

 tossed into wave-Kke plications or folds : and in another passage, 

 speaking not especially of the Highlands, but generally of the Earth's 

 crust, he says that " there is no dispute regarding the abundance of 

 the upheavals, subsidences, and dislocations which it has undergone." 

 But these general admissions are but a poor compensation for the 

 silence which Mr. Geikie maintains on a whole class of the most 

 important facts connected vrith the structure of the country. It 

 would have been more satisfactory if he had included in his descrip- 

 tions some notice of the appearances of subsidence and dislocation 

 which are to be observed in that particular part of the Earth's crust 

 which constitutes the West Highlands, and especially if he had 

 given us some account of the relation in which the dislocated 

 sedimentary rocks stand to masses of granite or of other apparently 

 intrusive rocks. But this is a subject, surely one of the most im- 

 portant of all, on which we derive no information whatever from 

 Mr. Geikie's volume. There is, indeed, a passage in which he 

 asserts that the convolutions of the old crystalline rocks " cannot be 

 assigned to grand primeval eruptions of Granite." The reason which 

 he assigns for this assertion is, that although granite rises up among 

 the highest mountain groups, " it also occupies wide spaces of low 

 ground," a fact which, so far as I can see, has no bearing whatever 

 on the question. Mr. Geikie then throws off in a single passing 

 sentence a theory as to the origin of granite, which he produces no 

 facts whatever to justify, and which, again, even if it were true, 

 would in no way decide the question how far the manner in 

 which the contorted sedimentary strata are associated with Granitic 

 rocks does, or does not, indicate the predominant effect of subter- 

 ranean movements on the present physical geography of the countiy. 

 " Indeed," says Mr. Geikie (and this is the sentence to which I refer), 

 *' there is good reason to believe that granite is not an igneous rock in 

 the ordinary sense, hut that, instead of bursting through and upheaving 

 the Gneiss and Schist, it is itself only a further stage of the metamor- 

 phisrn of those rocks'' What Mi\ Geikie means by " igneous in the 

 ordinary sense of the word,'' can only be conjectured. If he means 

 that granite is not " igneous " in the same sense in which trap is 

 igneous, I quite agree with him ; but then I thought this is now 

 pretty generally accepted and understood. It has, however, nothing 

 whatever to do with the question before us. It may also be true 

 that granite is composed of materials originally derived from sedi- 

 mentary rocks, and that it represents only a further stage of meta- 

 morphic action. But neither would this proposition, even if {^ were 

 established, which it certainly is not, in the slightest degree affect 



