GLACIO-AQUEOUS ACTION IN NORTH AMERICA, 215 



Rocky Mountains, show that all the northern parts of our conti- 

 nent must have been above the waters long before the period of 

 drift : for our tertiary strata are covered with drift, so that the 

 agency which produced it must have continued to act, at what- 

 ever time it began, up to the commencement of the historic or 

 alluvial period. Hence, after the deposition of the coal strata and 

 the new red sandstone, the continent must have experienced 

 such a depression as to bring the ocean over the whole of it, in 

 order to produce the striae and accumulations of drift. After- 

 wards, it must have been raised to its present height above the 

 waters. Now who is prepared to believe that this continent has 

 experienced such vast vertical movements so recently ? Espec' 

 ially who can believe that the vast chain of the Alleghany moun- 

 tains, more than six thousand feet high in New Hampshire, has 

 all been beneath the ocean since the deposition of the tertiary 

 rocks ? And since we find the drift from all other formations 

 spread over the tertiary, T do not see but every place from whence 

 it was derived, must have been beneath the waters when it was 

 accumulated. 



It may be said, however, that our older mountains may have 

 been above tlie waters long before the tertiary rocks ; and that the 

 marks of glacio-aqueous action on those mountains may have been 

 produced an immense period of time earlier than that in which 

 similar effects took place upon the newer formations. But 

 to this idea I oppose, first, the fact that the phenomena of cbift 

 have an almost equal freshness and apparent recentness on the 

 oldest and the newest rocks : secondly, the fact that bowlders 

 have been can-ied, in many instances, from lower to much higher 

 levels : ihu'dly, the fact that the northern slopes of our moun- 

 tains are often striated, several hundred feet below their summits, 

 by a force directed upward. Finally, if our higher mountains 

 were above the waters before glacio-aqueous agency took place 

 at lower levels ; if, for instance, the ridges of the Alleghany chain, 

 from Alabama to Canada, w^ere diy land when this agency was 

 in operation upon the lower rocks along the Atlantic coast, then, 

 I ask, how the drift could have been carried southeasterly from 

 the ridges already above the waters ; and how the striae should so 



