tT 



426 GEOLOGY OF THE SECOND DISTRICT. 



that llie views of Mr. Murchison* in this particular accord with all that I have observed in the 

 Second district. 



There remains one fact to be explained, namely, the removal in many places of the upper part 

 of the tertiary ; for it is only, as has been stated, perfect or entire in some sheltered places. 

 It is swept away by some cause ; and though I have suggested in several places in the report, 

 that a current swept over the country, and bore the tertiary along south, yet this explanation 

 is not very satisfactory. I would rather adopt the opinion or theory, that during its rise, after 

 its submergence and the completion of its beds, they were destroyed by the action of w.aves ; 

 and I take this opportunity to say that I am the more inclined to the latter, inasmuch as I wish 

 to see things done in the most quiet way possible. I care not how long it takes. I have even 

 been inclined to exclude from my list of causes, those mighty waves, enormous debacles, and 

 hemispheres capped with ice ; they have always appeared to me to be out of keeping with the 

 order of things established on this planet. 



The boulder system of the western slope of the Green mountains, although in proximity 

 to that of New-York, is quite different from it. The Taconic rocks, together with the 

 Champlain group of the New-York system, form this slope. This system I have described 

 as narrow and long ; and although it extends far north and south, yet I have been unable to 

 discover upon this belt the boulders which abound west of Lake Champlain. 



We may divide the region which lies between the western shore of the St. Lawrence, and 

 the eastern limit of the Taconic system, into three belts running north and south : The eastern 

 belt takes in the western slope of the Green mountains, and parts of the valleys of Lake 

 Champlain and the Hudson river ; the middle belt commences on the east with the eastern 

 slope of the northern highlands, and extends to their western slope ; and the western belt 

 comprises the valley of the St. Lawrence, and the region extending along the southern border 

 of Lake Ontario to the foot of Lake Erie. In the first, the boulders of the rocks of the Taconic 

 system prevail. At this moment, I do not remember to have seen a rock of granite, horn- 

 blende, hypersthene or primary limestone, except upon the very eastern border, where it lies 

 adjacent to the granite of the Green mountains. The middle belt abounds, from the northern 

 slope into Canada, quite down to the Sound, with hypersthene, gneiss, hornblende and primary 

 limestone. The western belt is distinguished by hyperslhcne, and the granites of the far north. 



The hypersthene boulders abound, as has been stated, on the shores of the St. Lawrence 

 and Ontario ; and are found far south in Erie county. Their origin is clearly not in Essex 

 county ; for in that case, as has been stated, we should be able to trace them to their source, 

 along the western slope of the mountains, up to their parent rock in that county, just as we 

 can trace those which are found on the southern slope of the same mountains. 



The point of greatest interest to myself among these facts, relates to the extreme narrow- 

 ness of the belt occupied by any given system of boulders ; which fact seems to be demon- 

 strated, if reliance can be placed upon the observations already made. 



• Murchison's Address at the Anniversary Meeting of tlie G. S. of London, 18tli Fcl)ruary, 1842. 



