ON THE ORIGIN OF COAL, 



159 



regularity, and Coal is found on the deposit 

 showing the greatest quietude of formation, which 

 is nearly in all cases the floor. 



Little evidence is at present to be had of the 

 power of moving water, to remove bodies im- 

 mersed in it, or which obstruct its progress, 

 and further experiments require to be made. 

 In vol. 49, No. I, p. 2, of Professor Silliman's 

 American Journal, Mr. Mather, in a paper on 

 the physical geology of the United States, gives 

 the following table of the transporting power 

 of water : — 



POWER OF TRANSPORT. 



Wears away fine compact tough clay 

 Removes fine sand 



Sand as coarse as flax seed. . 



Fine gravel 



Pebbles of an inch in diameter 



Angular fragments, 2 to 3 inches 



This last indicates a current, sufficient to move 

 the largest pebbles found in the rough rock, one 

 of the coarsest grained beds of the Coal measures. 



Being best acquainted with the Lancashire and 

 Cheshire Coal-field, it may be as well to mention 



