GREY SANDSTONE. 125 



has so long furnished the hme for the cities of Troy and Albany, and the villages to the north. 

 This rock, though it is high in the Transition system, contains no fossils of any description. 



4. A Tcenish breccia, whose fragracnls are not coarse, but very strongly compacted or cemented together. Its 

 coloring matter appears often to be chloritic ; and when Ihe mass is fine, it has a trappcan appearance. 



This variety is rather to be regarded as existing in beds, or inclosed in the sandstone. It 

 is the typical greywacke of authors. It resists disintegration for a long time, and the beds 

 are scarcely acted upon by the weather, which neither softens nor discolors tlic mass. Veins 

 of spar and quartz traverse it in all directions, and hence it appears chequered, which, how- 

 ever, cannot be safely considered as identifying the rock. Like the limestone noticed above, 

 it is entirely destitute of fossils. 



The finer kinds of breccia, and coarse sandstone, when not too hard, form a very good 

 building stone. They are extensivel}' used in the construction of buildings, both public and 

 private, and in the fortifications of Quebec. The thick massive beds have not been much 

 employed in this State for construction, but the slaty varieties are extensively used for flagging. 



5. A conglomerate, consisting of rounded pebbles of quartz, united apparently without the intervention of a 

 cement. 



This conglomerate is confined to Oneida county. It is a hard unyielding mass, and is 

 much inferior, as a building material, to either of the preceding varieties. It is destitute of 

 fossils. 



Of this limestone, it is necessary to remark, that it resembles so nearly another limestone, 

 or one which I now suppose belongs to a different period, that it is exceedinglj'- dilficult to 

 distinguish them. The one I now speak of, certainly occupied the position which I have 

 given it, above the grey sandstone ; but there is another in the primary of the Taconic range 

 farther east, in the slates of which the range passing through Pownal in A'ermont, and Wil- 

 liamstown, Pittsfield and Riclmiond in Massachusetts, are examples, which resembles it so 

 strongly, that I have at times been disposed to consider the two as one and the same rock. This 

 acknowledgment may not speak very well of my discriminating powers, yet I would shelter 

 myself from the charge by stating some of the difficulties : 1 st, neither rock contains fossils ; 

 2d, their lithological characters are not remarkably different ; 3d, they are both sometimes 

 associated with slates, which also resemble each other ; and in the 4th place, they lie along 

 a disturbed district. I hope, however, yet to clear up all the difficulties of the case : in fact, 

 my mind is made up, but I am in want of some facts to satisfy others that my conjectures 

 are right. 



The limestones of Berkshire county have been fully and ably treated of by Profs. Dewey 

 and Hitchcock ; but that which rests upon the rocks formerly denominated greywacke, has 

 not been noticed at all in geological works, in a way which would enable inquirers to recog- 

 nize it. I gave a diagram illustrative of its position, as well as of the rocks beneath, in the 

 Report for 1838, but omitted the main facts relative to its distinctive characters. 



This limestone is rarely a homogeneous mass ; but, as has been observed in almost all 



