34 [Assembly 



3. Tlie Stratified fossil-bearing rocks, covering all the State 

 except the two districts above mentioned. 



We will now describe them more in detail, beginning at the 

 lowest and proceeding upward. 



Of the Hypogene and Metamorphic rocks, however, we shall 

 add to what has been said but very little. They cover, as has 

 been before remarked, two separate tracts of country in this 

 State, one in its southeastern part; the other lying in 'the cen- 

 tral portion of the great triangular area bounded by the Mohawk, 

 the Champlain and the St. Lawrence valleys. On the geological 

 map of the State, the territory which they occupy is marked by 

 a coloring of deep pink. 



The various kinds or varieties of these rocks are mingled in 

 great confusion over most of these tracts, seeming often to 

 change or gradually pass into each other. The metamorphic 

 masses of gneiss, mica-slate, crystalline limestone, etc., are more 

 fully exposed (as a general rule) around the edges of the tracts, 

 where they pass under the higher strata of fossiliferous rocks ; 

 while the granite, hypersthene, and other hypogene masses are 

 more fully developed near the centres of these areas, and among 

 the highest of their mountains. 



In the southeastern part of New- York these rocks occur gene- 

 rally in small areas, seeming to be interposed among the gneiss 

 and other metamorphic masses, as if they had broken up here 

 and there through fissures or clefts. A very remai-kable instance 

 of this is on the lower Hudson. The rock at the level of the 

 river is a horizontally stratified red sandstone ; but through 

 some fissures or rents now concealed, vast volumes of melted 

 rock have formerly been forced up, which have overflowed the 

 sandstones to a great depth, and in cooling have assumed the 

 rudely crystalline or columnar structure so common in basaltic 

 or trap rocks. The broken or worn edges of this enormous pile 

 of trap, fronting on the river, forms the precipice so well known 

 as ''the Palisades." Yeins of granite are seen in many places on 

 the island of New- York, penetrating in every direction the gneiss 

 rock which forms the mass of its territory. 



In the hypogene and metamorphic region of Northern New- 

 York, the higher mountains seem to be chiefly composed of gray 

 '^ hypersthene " rock, made up chiefly of felspar. Granite, trap, 

 serpentine, and many other varieties of similar rocks of igneous 

 origin, are found in all parts of the district, and so intermingled 



