354 D. Bell — The Great Ice Age and Submergence. 



of shallow shore there could at any time be at Clava, is a difSculty 

 in this respect. Farther, on this theory the transition ought to 

 be gradual ; as the area of the sandstone narrowed a smaller and 

 smaller proportion of sandstones should appear, till at length the 

 schists predominated. But here the change is sudden and complete 

 at the very bottom of the clay. As the Report says, " The boundary 

 line between the shelly clay and underlying gravel is clearly defined. 

 There is no intermingling of the two deposits" (p. 4). Similarly, 

 the line of junction between the shelly clay and the overlying sand 

 is "clearly defined" (p. 3). There seems thus to have been a 

 sudden and complete change of conditions during the deposition of 

 the shelly clay, not to be accounted for by submergence — not even 

 l3y a "rapid and brief" submergence, overlooking for a moment the 

 intrinsic improbabilities of such a supposition, and its contrariety to 

 the other facts of the case. For, as Mr. David Robertson remarks 

 in his valuable Report, " the clay seems to indicate deposition in 

 still water, showing no traces of sti'ong currents." There was very 

 little sand in it ; 90 per cent, being fine mud or silt. This is not 

 consistent with the theory of a "rapid and brief" submergence. 

 But how, in any case, could there be " still water " and no strong 

 currents here if this were then a shore of the northern sea, and 

 immediately adjacent to, nay, actually swept by, the strong tides 

 and currents that must then have flowed to and fro through the 

 Great Glen ? We can scarcely imagine a locality where, during 

 the supposed submergence, there would be less likelihood of " still 

 water " than at Clava. 



Thus, the more it is considered the more do difficulties accumulate 

 round the theory of a submergence to this extent, which, besides, 

 there is absolutely no independent evidence to support. And all 

 these difficulties and objections, if real and well founded, are so 

 many arguments in favour of the ice-transport theory, which (as 

 Professor Ramsay admitted with regard to the analogous cases of 

 Holderness, etc.) is the only alternative.^ 



We think we may now claim to have shown that the ice-transport 

 theory, as applied to this Clava deposit, is, on the whole, much 

 more probable than the theory of submergence. This is all that 

 is required to vindicate the position of the minority'. They did not 

 undertake to say what was the precise mode in which the deposit 

 was conveyed or accumulated ; thej' merely expressed their opinion, 

 " with all deference," that the submergence theory was not satis- 

 factory, and that the Committee had " not yet reached a solution of 

 the difficulties " connected with the deposit. 



Here, therefore, our remarks might end. But the present writer 

 is now prepared, on his own account, to offer a further suggestion 

 which may perhaps lighten the difficulties still felt, in some respects, 

 to exist. We have said that, if transported by the ice, it does not 

 " necessarily follow " that the whole of this deposit was conveyed 

 simultaneously, or en masse. Briefly, our idea is that it may have 



1 Phys. Geol. and Geog. of Great Britain, p. 157 (3rd edition). 



