134 Progressive Changes of Matter. [March, 



upon it ; that such was the fact, the drift of a high northern ori- 

 gin is the proof. 



To most readers it may be unnecessary to mention, that the 

 field stones of which we have spoken, and which so oiten are ob- 

 served, are but iiagraents of rocks that were once masses and 

 stratified ledges, and that by being broken and shattered by 

 subteranean disturbances, were once a mass of blocks similar to 

 quarry stone, and that subsequently, they were driven along by 

 water currents, and being rubbed and jamed against each other, 

 were lounded and smothed ; when theiefore, we find the part of 

 the origninal rock left, it is called the parent rock ; a rock in 

 place. In this way we can determine the general course of an- 

 cient rivers. 



The manner in which drift materials was generally desposited, 

 is more conclusive evidence of an inclined surface over which it 

 was moved than any that we have heretofore brought forward. 

 This fact established, then every rain would of itself produce a 

 flood ; and drift banks formed by this flood left their materials 

 jumbled together in all possible admixtures and internal arrange- 

 ments as we now see them. Another fact in relation to currents 

 should be observed ; the tendency they have when wearing away 

 drift material to form falls or steps in their channels, a fact ever 

 to be noticed whether the stream be large or small, and as these 

 chasms become filled up in the advance of the drift, they were but 

 the repository of fine, as well as coarse material. 



We have frequently observed in gravel banks through which ex- 

 cavations have been made, both by running watei and the labors of 

 man, a stratum of sand beginning and terminating within the dis- 

 tance of a few rods, and no place to exceed a foot in thickness, 

 above and below which, were layers or beds of gravel with large 

 field stones, and sometimes in the same bank strata of the finest 

 clay. It is evident fiora this fact that the character of the current 

 and the position of the material underwent a striking change 

 when the bank was formed. It certainly could not have been 

 a deep, strong uniform current that deposited matter in this form. 



We will now proceed to notice some of the last and striking 

 evidences these great ancient rivers have left of their labors. Bv 

 turning to the figure we have given, it will be observed that the 

 part of the Onondaga limestone that remains, has a southern in- 

 clination. The average distance from its out-crop to the Mar- 

 cellus shales and the HamiUon group, in the towns of Warren 

 and Columbia, is from 5 to 6 miles. A range of hills composed 

 of the latter groups in place, skirt its southern border. On this 

 area large oblong piles of drift remain. These ridges are com- 

 posed of coarse and fine drift, generally of a bluish cast, and in 

 many places indurated to the almost hardness of rock. Field 



