290 



same succession of beds as seen at Mullica Hill. The upper 

 stratum invariably consists of little else than the green granules, 

 their colour being a light verditer green, and on drying rarely 

 presents the white crust upon the grains seen in the darker sort. 

 The dark green bed possesses a larger share of dark clay inter- 

 mingled with the grains, which, according to its hue, imparts 

 different tints to the stratum. The grains themselves are not of a 

 very deep green. In Dr. Swing's neighbourhood, the lower bed 

 alone is used, under the impression, not based upon experience, 

 however, that the other is inert. This lower marl has proved 

 to be highly beneficial, the evidences of which may be seen upon 

 Dr. Swing's farm. Yet this lower bed is apparently identical in 

 all respects with the lower stratum at Mullica Hill, where it is 

 pronounced equally inefficient with the upper. This fact ought 

 to show us how many experiments remain to be made before we 

 can pass a final judgment upon the non-existence of fertilizing 

 properties in any of these marls. The lower bed here contains 

 but few shells. At Woodstown there is one layer containing a 

 prodigious abundance of the gryplied convexa,^x\d a less propor- 

 tion of one or two other species. Sharks' teeth, and the bones of 

 the fossil crocodile are not uncommon. The shells possess but a 

 small amount of lime, much of it having been dissolved away, 

 and its place supplied by oxide of iron, from which they derive 

 their brown ferruginous colour. Their presence is therefore of 

 little or no benefit to the marl. 



Marl from the farm of Dr. Swing, near Sharptown. 



Description. — Colour, dark earthy-green; the washed grains 

 of the same colour, and large in size. 

 Composition. — In 100 parts: 



Greensand, - . - 91'20 

 Clay, - - - - 8-80 



Quartzose sand, - - none. 



10000 

 Potash, by direct examination, 10 per cent. 



Four miles to the southwest of Sharptown, the surface of the 

 country suddenly drops twenty-five feet, or more, to a lower level 



