124 GEOLOGY OF THE SECOND DISTRICT. 



the particles of which it is composed are not large, yet they are united very firmly together 

 by a green argillaceous cement, similar to chlorite, the matter of which was probably derived 

 from the chloritic slate which forms the eastern boundary. From the same source, too, the 

 hyaline quartz was derived ; or at least it bears so strong a resemblance to the quartz of the 

 talcose slates of the Taconic range, that it cannot be distinguished from them. 



The differences in the sandstones of the two regions does not stop here. There are two 

 additional facts to be stated : 



1 . The sandstone west of the Taconic range is often brown or reddish brown, especially in 

 Vermont, on the eastern border of Lake Champlain, as at Addison, Charlotte, Burlington 

 and Colchester ; at all of which places, the beds of sandstone are interlaminated with a red- 

 dish shale. 



2. The fact of the most importance, is the termination of the sandstone in a grey or white 

 limestone, which may be seen at the places already named. 



To complete the view of this rock, we must take into our description the mass of con- 

 glomerate at or near Utica, which I have no doubt is really a part and portion of the grey 

 sandstone. It represents, it is true, the whole mass ; and it is also true, that some geologists 

 regard this as a superior rock. It rests, however, upon the Lorrain shales, and bears no 

 distant resemblance to the conglomerate belonging to the greywacke. 



If the preceding views are correct, the masses belonging to the grey sandstone may be 

 enumerated as follows : 



1. A greenish, fine-grained, even-bedded sandstone, with thin green slaty layers interposed, and sometimes in- 

 closed also in the rock. 



This variety prevails in Jefferson county ; its territory is limited, and it is found better 

 developed in the covmty of Oneida, south of the Second Geological District. It is employed 

 for flags, grindstones, etc. and constitutes an excellent material for btiilding. A few fossils are 

 found in the lower part of it, but none which differ from those in the formation beneath. 



2. A reddish brown, or chocolate-colored sandstone, whose layers vary in thickness from four inches to two feet, 

 and alternate with thin laminated shales of the same complexion. 



This variety does not exist in the counties assigned me ; it is, however, the predominating 

 sandstone on the eastern shore of Lake Champlain. It is crystalline, or breaks into rhombic 

 masses. Quarries of this rock do not work kindly ; neither are the layers readily shaped, 

 and they are hard, approaching to vitreous. Thickness about seventy feet. 



3. White, grey and reddish limestone, terminating downwards in the preceding rock. Its beds are always thick, 

 and the whole rock is massive, and checked by seams of spar and quartz. 



This limestone is always impure, or siliceous, in the lower part, but becomes purer towards 

 the top of the mass ; it also loses its tinge of brown, and becomes white. It is often a pure 

 white limestone, but its particles are always fine ; or, in other words, it never becomes the 

 saccharine limestone of the Taconic system. It is the limestone at Bald mountain, which 



