24 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 17, 



stated at 2200 feet above the sea, I have found rolled quartz pebbles 

 and other proofs of aqueous action. There seems thus no doubt that, 

 supposing the land uniformly depressed, the whole range of the Pent- 

 lands, and the hill with these boulders on it, along with the others, 

 must have been submerged. Now if coast-ice could carry the boulders 

 up to the top of the hill during its gradual subsidence, it should also 

 have lifted them ofP the top of the hill when it was finally submerged. 

 There seems no reason why the ice should continue to raise the 

 blocks just so far as the summit of the hill, and then cease to have 

 this elevatory power. 



The theory which I should substitute in place of this most inge- 

 nious one, is that of unequal elevation in different parts of the land. 

 That this has taken place to a very considerable extent, the phseno- 

 mena of the surrounding district most distinctly prove. We now 

 find portions of strata, which there is every reason to believe were 

 once continuous, separated by many hundred feet of vertical eleva- 

 tion : the workings in the surrounding coal-field prove this most 

 emphatically. In the memoir on the Mid-Lothian coal-field already 

 referred to, Mr. Milne enumerates fifty-two slips raising the strata to 

 the south 5169 feet, and thirty-seven others which raise them 2412 

 feet in the opposite direction ; the most extensive slip having thrown 

 the strata 400 to 500 feet down to the north. In the coal-fields on the 

 north of the Firth of Forth slips are no less numerous, but there those 

 elevating the strata to the north preponderate, producing a difference 

 of 1164 feet in twelve miles. A single fault in the eastern part of 

 Fife amounts to 600 feet, and in the Clackmannan coal-field two slips 

 are known, one of 700, the other of 1230 feet; all of them raising 

 the strata on the north. The difference of elevation indicated by these 

 faults seems sufficient to account for boulders having been transported 

 from what is now a lower to a higher level. 



The strongest objection to this mode of explaining the transportal 

 of boulders from lower to higher levels seems to be, that we see no 

 traces of unequal elevation on the present surface of the ground. But 

 this objection leaves out of view the important changes which must 

 have taken place on the surface since the land was raised above the 

 ocean, and especially those connected with that process. During 

 these changes, many inequalities which once existed must have been 

 smoothed down, covered over, and obliterated, so that scarce a trace 

 of them now remains ; the effect of the last change being always to 

 destroy the marks of those that preceded it. But if we suppose that 

 the elevation of our present continents resembled that which we know 

 is now taking place in Scandinavia, where one end as it were of a 

 lever is rising, whilst the other remains stationary or sinks, we may 

 have a very great amount of unequal elevation without any break in 

 the continuity of the strata, or any proof of its having occurred being 

 left on the surface of the dry land. A difference of angular motion 

 amounting to one degree, producing an inclination so small as to be 

 imperceptible to the eye, would be sufficient to account for the whole 

 phsenomenon. Were the country between London and Anglesea 

 subjected to such a twist, we should have that island sunk 20,000 feet 



