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- 
iDndary 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- 
