104 



GEOLOGY OF THE SECOND DISTRICT. 



fortable appearance. The rock dips 25° to 30° to the northwest, at Potsdam ; but situated 

 as it is, adjacent to the primitive rocks, it presents every degree and variety of direction and 

 dip. 



Tiiougli this rock is generally even-bedded, I have noticed several places where it has been 

 subjected to violent forces, so as to greatly derange the strata. A remarkable instance exists 

 at Dekalb in St. Lawrence county, where the rock, in addition to an elevating force acting 

 beneath it, seems also to have been subjected to a lateral pressure, by which the strata are 

 folded around each other, a representation of which is exliibited in the wood cut fig. 31. In 



the cut, the edges of the strata only are seen, and but a small part of the mass so affected is 

 exhibited in the drawing. The locality is about eighty rods north of the village of Dekalb, 

 on the roadside, and can scarcely escape the notice of the most careless observer. Other 

 portions of the same mass show more clearly the effects of lateral pressure ; so much so, 

 that some parts of the strata are perfectly crushed or broken up, and appear in fragments, 

 which are displaced as in the cut fig. 32. The rock immediately beneath this disturbed mass, 



IS primitive limestone. The junction between them is concealed, and we are left to conjec- 

 ture as to the immediate cause of this remarkable disturbance. 



The Potsdam sandstone, during the accumulation of its materials, appears to have been 

 subjected to a variety of changes in the liind of the materials of which it is composed, and the 



