265 



i-acterized by ostrea falcata, to occupy a yet lower place in the 

 series. 



Marl from the farm of William Imlay, between Plattsburg 

 and Arneytown^ Burlington county. 

 Description. — Colour, dark olive-green ; washed granules, dark 

 clear green, and of large size. 

 Composition. — In 100 parts: 



Greensand, - - - 91-85 

 Clay, .... G-65 



Quartzose sand, - - 1-50 



10000 

 The proportion o( potash in this marl, deduced from that of the 

 greensand, is 10-5 per cent. 



Marl from, Crosswicks creek, at its intersection with the Mount 

 Holly and Monmouth road. 

 Description. — Colour, dark earthy green. 

 Composition. — In 100 parts: 



Greensand, - - - 82-22 

 Clay, .... 13-58 



Quartzose sand, - - 4*20 



10000 

 The proportion of potash in this marl, as deduced from the 

 greensand, is 9*6 per cent, 



Plattsburg, or Sykesville. — Marl of excellent quality is procured 

 at several places in this neighbourhood, as the following analyses 

 will show. 



Marl from Poke Hill, near Plattsburg, Burlington county. 

 Description. — Colour, a greenish olive-gray; washed granules, 

 a rich dark olive-green, rather above the medium size. 

 Composition. — In 100 parts: 



Greensand, ... 98.0 

 Clay, .... 20 



Quartzose sand, - - none. 



1000 

 23 



