Apparent objections to the Glacial Theory, 295 



those continents had taken place, the swell occasioned in the ocean 

 by such uprise would have forced back the diluvial wave, bearing 

 with it the fragments of various rocks which had been shattered by 

 the movement, and these would have been dropped sooner or later 

 according to their weight, over those tracts traversed by the re- 

 tiring waters. But it is not to be supposed, as Bake well judiciously 

 observes, that such a swell could suddenly subside ; it would return 

 over the land repeatedly at a lower and lower level each time, until 

 its force being expended and the equilibrium once more restored, 

 it would have deposited those lighter materials which had become 

 sorted by the movement of the water, above the heavier boulders 

 and detritus.— See BakeweWs Introd. Geol. passim. 



Thus the heavy blocks forming the lower portion of the Glenairn 

 moraine, and those scattered over the lower land at Cortachie, 

 would appear to be precisely in the position, supposing water to 

 have been instrumental to their deposition, which their greater 

 specific gravity would demand ; while the lighter gravels and sands 

 which form so thick a stratum above them, are likewise the produce 

 of the same waters as their force and powers of suspension dimi- 

 nished. Nor is it at all necessary to suppose, that all our lands were 

 at once uncovered by this outburst, for when once the mountains 

 had been upheaved by the volcanic action within the earth, the 

 subsequent movements may have been more gradual and similar 

 to what is still taking place ; the mounds or accumulations of 

 debris would therefore have remained uninjured beneath the waters, 

 until the uprise of more land in various quarters had caused the 

 ocean to retire, and left the diluvium to the action of rivers and 

 streams as the drainage of the land proceeded, while its own retire- 

 ment would have denuded the strata to which it had previously 

 given rise. Lyell supposes, that the detritus at Glenairn is the 

 production of a glacier whose dissolution caused a body of water to 

 accumulate, until it "overflowed the mound and furrowed out the 

 softer materials composing the upper part into ridges and hillocks." 



This is obviously incorrect, or he not only shows us elsewhere, 

 that the distribution of land and sea previous to the historical era 

 was such as to banish nearly all signs of frost from the earth, but 

 that the rise of land in the north has continued ever since the com- 



2 Q 



