30 Dugald Bell — The " Greai Submergence." 



grey till foi'med from tlie native rocks contains no marine 

 organisms, which are restricted to sands and clays containing (like 

 the Caithness shelly Boulder-clay) fragments of rocks foreign to the 

 district, and which seem to have been borne inland along with the 

 shells, etc., from the sea. (See Peach and Home on the Glaciation 

 of Caithness ; Jamieson on the Shelly Clays and Gravels of 

 Aberdeenshire.) 



(5) Again, supposing such a depression and collapse of the 

 earth's crust, say over the area of the British Isles, or a great part 

 of it, where is the probability that the sunken part, after some 

 tens of thousands of years (in all likelihood), should re-emerge, 

 presenting much the same aspect as before, the same general 

 arrangement of hills and valleys, the same climatic conditions over 

 again, with very little to show for the prolonged submergence, 

 except a few stray patches here and there of shelly clay, the very 

 paucity and the distribution of which suggest that their present 

 position is due to another cause ? 



The difficulty is not the submergence alone (though that is 

 sufficient, without the very clearest proof, when one of such 

 magnitude is concerned) , but the submergence plus the re-emergence 

 that followed. 



(6) Another consideration, which has been alluded to more than 

 once of late years, is that such a submergence would in all probability 

 be accompanied by much milder climatic conditions, of which 

 marine organisms found at high levels, if in place, would furnish 

 clear indications. (See Lord Kelvin " On Geological Climate," 

 Trans. Geol. Soc. Glasgow, vol. v.) 



We submit that these objections, and others that might be stated, 

 ought to be considered and answered in some degree before we are 

 asked still to accept the old, crude, " rough and ready " theory of 

 a " great submergence." It is worthy of note, ere leaving this part 

 of the subject, that the objections which have been urged, of late 

 years especially, to such a submergence in this country ai'e precisely 

 similar to those which the American geologists have urged with 

 unanswerable force in regard to certain high-level tei-races that were 

 formerly supposed to be sea-beaches, but are now clearly made out 

 to be old lake-margins. A general subsidence of the country was 

 the theory formerly adopted. But as Professor G. F. Wright states 

 the case — " There is no such amount of collateral evidence to support 

 the theory of general subsidence as there should be if it had 

 really occurred. The subsidence of the lake x-egion to such an 

 extent would have left countless other marks over a wide extent of 

 country, but such marks are not to be found. Especially is there 

 an absence of evidences of marine life. The cause was evidently 

 more local than that of a general subsidence." (" Ice Age in North 

 America," p. 353.) 



In our next we shall consider the pros and cons — especially some 

 of the alleged cons — of the alternative, or ice-transport, theory. 



