276 



pits of Mr. Buck, J. P. Rogers and others, are very extensive. 

 At the former, which are low, the marl is of a pretty light bright 

 green; upon drying, it does not become covered with much 

 efflorescence. The excavations enter the stratum about ten feet ; 

 no shells or other fossils are seen. The sand of the overlying 

 diluvium contains some of the green granules, and a layer which 

 has somewhat the aspect of a green clay, derived perhaps from 

 the granular marl below. That this overlying bed is certainly 

 diluvium, is proved by the fact of its occasionally filling troughs 

 or undulations in the top of the marl, which seems to have been 

 furrowed at some time by rapid currents sweeping over its surface. 



At J. P. Rogers', the colour of the marl is darker, being a deep 

 dull bluish green. These varieties in colour are due more often 

 to small admixtures of differently coloured clays than to an in- 

 trinsic difference in the tints of the granules themselves. The 

 marl now before us exhibits a copious white efflorescence on 

 drying. It is certainly a curious fact, but is true, as f;ir as I have 

 yet observed, that the darker marls have more of this than the 

 light ones. The dark and light green varieties in this quarter, 

 seem not to be, as in many places elsewhere, distinct beds. At 

 the depth of about ten feet numerous fossils occur. Besides the 

 ordinary shells, there have been found sharks' teeth, and a por- 

 tion of the jaw of a crocodile, containing three of the teeth in 

 their sockets. A small mass of a black bituminous substance 

 possessing all the characters which belong to mtinasp/ialtum, 

 was procured two feet beneath the top of the marl. It is iden- 

 tical in all respects with the mass found near the top of the marl 

 at Forsyth's. 



At Cooperstown, upon Cooper's creek, five miles from Camden* 

 there is a marl much in use throughout the neighbourhood ; it 

 lies near the surface, being covered by a yellowish mottled bluish 

 clay, apparently the same with the bj-ick earth upon which Phila- 

 delphia stands. 



It has been penetrated in pits which are dry, to the depth of 

 twenty-four feet. It is a tough unctuous bluish clayey stratum, 

 with only a moderate per-centage of the green granules, and a 

 considerable amount of ^the astringent matters, (copperas, &c.) 

 It contains numerous shells, some of them of great size, an oxygra 

 costata found in it weighing upwards of nine pounds. 



