244 Remarlcs on the Geology of Western New YorJc. 



action is probably in all cases a matter of accident, if I may so speak 

 of any of the great phenomena of nature, it follows that in deter- 

 mining the relative age of rocks, these appearances must be left 

 entirely out of the account. 



Although the ordinary and more palpable effects of volcanic action 

 are not discernible, it would seem, from the highly crystalline tex- 

 ture of much of the limestone, that it had been subjected to a con- 

 siderable degree of heat, many of the fossils having been nearly 

 obliterated, and having assumed the same crystalline texture as 

 the rock itself. In some places this limestone contains numerous 

 geodes of crystals, consisting principally of calcareous spar, do- 

 lomite, selenite, snowy gypsum, and celestine. Very small crys- 

 tals of quartz also sometimes line these geodes, and show through 

 the transparent selenite with a splendent lustre. Galena and blende 

 also occur disseminated in the upper layers at the Falls ; and green 

 malachite has been found at Black Rock. It resembles the moun- 

 tain limestone also, by containing in its upper strata numerous layers 

 of chert, or hornstone. At Black Rock, and many other places, 

 the siliceous part constitutes the greater portion of the rock, and 

 forms a building stone of great hardness and durability. Where the 

 calcareous portion has been disintegrated and removed by the action 

 of the weather, it presents an exceedingly harsh and jagged appear- 

 ance, and is most significantly called by the laborers -''chawed stone." 

 The caverns at Schoharie Kill, and at Bethlehem, are said by Prof. 

 Eaton to occur in this rock ; at which places, the imbedded fossils, 

 so far as I can learn, greatly resemble those found farther west. 



Thus far, I have not touched on the fossil characters of these sup- 

 posed secondary rocks : and it is here the geologist will look with 

 most confidence for those characters by which alone he can read the 

 history of those changes which have taken place on the earth's sur- 

 face to prepare it for the reception of his own species ; the last great 

 work of the days of creation. Did these rocks belong to the lower 

 secondary we should expect to meet with some vestige of a former 

 vegetation. Now what is the fact ? Not a fossil of vegetable origin, 

 nor the impression of a single leaf is met with. Those entombed in 

 these rocks are entirely of marine origin, and from.the entire absence 

 of marks of vegetation, it would seem they inhabited deep waters. 

 Madreporites, terebratulites, orthoceratites, milleporites, encrinites, 

 and corallines, make up by far the greater part. Others occur, some 

 of which I have not been able to make out. The trilobite, which 



