253 



of clay present occurring only as a thin coating upon the grains. 

 The lower part of this layer has a more yellowish hue from a 

 greater excess of the clay, which is here rather ferruginous. 

 The thickness of the bed is not known, though it has been pene- 

 trated sixteen or seventeen feet. 



I have witnessed its action on some very poor light soils, which 

 were rendered highly fertile from the use of this marl in a first 

 dressing of five loads to the acre, and an equal quantity at the 

 next rotation of the crops. 

 The best marl of Ely's bed exhibits the following 

 Composition. — In 100 parts : 



Greensand, - - - 80 



Clay, 20 



Quartzose sand, - - - none. 



100 



The amount of -potash in this marl, by calculation, is 9-2 per 

 cent. 



The following analysis shows the composition of another marl 

 of this neighbourhood, that from the pit of Mr. John Shaft, of 

 Shark river. 



The specimen was taken from near the mill, and is the best of 

 the several samples procured. 

 Cojnposition. — In 100 parts: 



Greensand, - - - 87 



Clay, 11 



Quartzose sand, ... 2 



100 



The amount of potash ascertained by analysis, is 9.5 per cent. 



Squankum. — Thorp's marl, near Squankum, presents the fol- 

 lowing varieties : 



1st; On the top, a bed of diluvial sand and gravel, and in 

 certain places a coarse, ferruginous sandstone, sometimes two 

 feet thick. 



2d. A light greenish-blue clay, the upper pan of which some- 

 times shades into a brown sandy clay, like the corresponding bed 

 at Shark river. One portion of this contains a small mixture of 

 the green granules. This portion appears, in fact, to graduate 



22 



