J^9G Apparent objections to the Glacial Theory. 



raenceraent of the tertiary period which preceded it, down to the 

 present time, and therefore that the climates of the earth are now 

 colder than they have ever before been ; from which it must follow, 

 that as no glacier now exists at Glenairn, so it never could have 

 existed there at all. 



Supposing, however, for the sake of argument, that such had once 

 been the fact, we shall still perceive that no furrowing of the mound 

 could have taken place from the melting of the ice, much less could 

 it have given rise to stratification ; for had the melting of the gla- 

 ciers been as sudden as M. Agassiz supposes their accumulation to 

 have been, vast deluges would have been produced, which instead of 

 heaping up debris at the mouths of glens, would have swept it all 

 off before the impetuous torrents, (See Hitchcock's Geol. passim J; 

 while on the other hand, had the thaw proceeded as gradually as it 

 does in the present day, where glaciers occur, the waters would 

 have escaped before the mound of detritus was completed, for it is 

 to the escape of the ice in the form of water that the moraines are 

 due, and until such escape is effected, no moraine is deposited. As 

 the ice melts, the water escapes, and the detritus falls down into a 

 confused and promiscuous heap without stratification ; the Glenairn 

 moraine therefore must owe its origin to some other cause. 



There is yet another circumstance which seems to me, to militate 

 against the opinion, that detritus and erratic blocks are due either to 

 the agency of glaciers or of icebergs. I allude to the rounded and 

 water-worn appearance which almost invariably characterises this 

 group of deposits. It is well known, that in the present day, the 

 detritus with which icebergs are occasionally loaded, is torn by the 

 action of frost from the shores where the ice is formed, and after- 

 wards floated away to be deposited in situations far distant 

 from their natural sites. Such fragments are either torn from 

 the solid rock by the expansion of water which has found a 

 passage into fissures ; or masses already detached are uplifted 

 from the shores and bottom of shallow waters. In the former 

 case, the fragments would exhibit their edges or angles for the 

 most part uninjured, while in the latter instance, the detritus 

 uplifted will, in all probability, consist of rounded water- worn frag- 

 ments, which have either been subject to friction in the situations 



