ST. LAWRENCE COUNTY. 



^CA 



This mass, if examined on the borders of the primary, is often exceedingly disturbed and 

 broken : the layers are often broken into short pieces, and cemented together again. An in- 

 teresting locaHty exists in Dekalb, a few rods north of the village, and by the road side. In 

 some instances the strata are crushed. 



This rock presents fewer varieties or kinds here than in Clinton county : the more regular 

 form is preserved. It is, however, often crystalline, in which state it assumes the form and 

 character of granular quartz. The lower portion is generally formed of a conglomerate, is 

 often quite coarse, and fragments of quartz as large as a peck measure are common. The 

 materials from which this rock is formed in this county, have been evidently derived from 

 granite. Fine particles of pale brown feldspar arc interspersed through the rocks, and the 

 peculiar character of the quartz indicates sucli an origin ; but a fact which sets this question 

 at rest, is found in the composition of the lower layers. Thus, at Dekalb, a conglomerate, 

 or rather breccia, is found, which is composed of pieces of granite containing a peculiar 

 variety of tourmaline wholly confined to this particular locality ; and while the origin of the 

 materials composing the rock is thus proved, we also prove that they were not transported far 

 from their original or parent beds. 



CALciFERors Sandrock. 



The limestone region is composed of this rock. The reader is therefore probably aware, 

 that in some places, particularly near the junction of the potsdam sandstone, this also wears 

 much the aspect of a sandstone ; but at a distance from their line of junction, the rock bears 

 the aspect of a limestone. 



This rock forms a belt or border along the St. Lawrence river, ten miles wide. Towards 

 Ogdensburgh it is much narrower, nearly runs out at Morristown, and entirely disappears 

 before it reaches Hammond. This rock is very much concealed by drift and soil throughout 

 this whole region : it lies low, and is never upraised much above the common level of the 

 country. The following towns are based upon this rock, namely, Lisbon, Madrid, Louisville 

 and Massena ; and it extends over a part of Brasher and Norfolk. 



Geol. 2d Dist. 46 



