34 



Proceedings. 



deposition of water on the earth's surface, which, flowing 

 down to the lowest levels, would form streams, lakes, and 

 seas ; and these, by their erosive action, would produce the 

 earliest sedimentary deposits, — resting upon the hollow 

 depressions of the hardening crust. There is no reason to 

 suppose that these agencies did not operate in varying 

 degrees on every part of the globe. But further. Some 

 geologists believe that the thirty thousand feet of Archaian 

 Laurentian rocks in Canada, and the smaller layers of 

 rocks of apparently the same age in the Hebrides, represent 

 the cooled and hardened crust to which reference has been 

 made ; in other words, that these never were aqueous 

 deposits, like the more modern strata occurring everywhere 

 on the Continent. In all probability we can now identify 

 no part of the ancient and primeval crust. Whatever it 

 was, it has most probably been melted and re-melted by 

 the subterranean heat which has also fused the older strati- 

 fied beds ; the primitive line of junction between the two 

 being thus wholly obliterated. The contraction of the 

 earth's crust, due to the causes already referred to, has 

 probably not entirely ceased even now. The marvellous 

 inflections of the contorted strata of the Alleghanies and 

 of the Alps, affecting Cretaceous and Oolitic rocks, have 

 in all probability been due to similar agencies, causing 

 lateral pressure ; we find that these disturbing forces have 

 operated more or less throughout every portion of what 

 is now dry land, all of which has been more or less 

 frequently under water ; this has been the case with even 

 the mountainous parts that now rise thirty thousand feet 

 above the sea-level from which they have been uplifted ; 

 hence it is difficult to believe that whilst such changes, 

 due to cosmical causes, were taking place on the great 

 continents, the corresponding areas now occupied by our 

 largest oceans were resting in a state of undisturbed 

 tranquillity. Dr. Williamson said it seemed to him that 



