GREEN SAND. — CRETACEOUS. 261 



consider the green sand group as identical with the 

 cretaceous formations of Europe. Of these fossils 

 there have been found over 100 species of animals ; 

 of which seven are of the class of large reptiles, in- 

 cluding three species of crocodile; two belong to fish- 

 es, one to a tortoise, and one to a wading bird ; while 

 of the other fossils, upward of 65 are remains of shell- 

 fish, corals, and other marine tribes low in the scale 

 of beings. Not a single one of these fossils can be 

 traced to belong to anything living in the present 

 day, and but one of these is common to the depos- 

 ites of both continents. Still there is a generic re- 

 lationship among the fossils of both deposites, al- 

 though a striking want of identity between the spe- 

 cies ; and this is sufficient to determine the place 

 Of the green sand to be somewhere among the sec- 

 ondary rocks, though it does not appear very evi- 

 dent whereabout in the secondary series of Europe 

 they should belong. 



Fossiliferous strata, referrible to the newest sec- 

 ondary or cretaceous period, occur in New- Jersey, 

 Delaware, Maryland, North and South Carolina, 

 Georgia, Alabama, Mississippi, Tennessee, Louisia- 

 na, Arkansas, and Missouri. It is this which forms 

 the " marl tract" or green sand strata of New-Jer- 

 sey, called marl, not from its resemblance to this 

 substance, but from its peculiarly enriching proper- 

 ties to the soil. This formation may be said to 

 cover the whole southern half of the state, bounded 

 by the lower edge of the rocky strata which lie 

 between Trenton and Perth Amboy. A line drawn 

 from a little below Trenton to the western side of 

 the Sand Hills, and from thence prolonged to Am- 

 boy, will cut off that southern portion of the state 

 which is underlaid by the green sand. From New- 

 Jersey the formation stretches across the State of 

 Delaware, and into Marlyand as far as the Sassa- 

 fras River on the eastern shore. Rocks of the same 

 secondary period, but of a different mineral charac- 



