XII CRETACEOUS AND TERTIARY FORMATIONS OF NEW JERSEY. 



The greater part of the State south of the Cretaceous and Eocene strata 

 is without fossils by which to determine its geological age. It is, however, 

 later than the Miocene, as is to be seen where they meet, and it is older 

 than the Glacial, as is shown where the glacial drift overlies the same for- 

 mation in some of the country immediately north of the Raritan. It ap- 

 pears to be regularly stratified, though all the strata are earthy, no rock 

 having been met in boring into it. Regular and extended beds of clay and 

 sand have been found in the various places which have been bored into, 

 but no fossils have been met with. In this state of our knowledge, it is 

 safe to call these beds representatives of the Pliocene age. 



The tide marshes, the sand beaches, and some low lying upland on the 

 borders of the sea and bay sides, are of the Quaternary period, and fur- 

 nish a few fossils which scarcely differ from the living species now found in 

 the adjacent tide waters. 



From the foregoing sketch of the geology of Southern New Jersey, it 

 will be seen that by far the greater number of fossils described in this work 

 are from the greensand beds of the Cretaceous formation. Fossils are 

 really much more abundant in these beds than in any of the others, and, 

 besides, these beds have been opened more extensively than any others on 

 account of the value of the marls which compose them, and which are used 

 for fertilizing the soil. 



Some of the species are very abundant, while of many others only 

 single specimens have been found, and very many of these forms have only 

 been found as imperfect casts. 



There is no complete collection of these fossils, and the Geological 

 Survey of New Jersey possesses only a small part of them ; for the remain- 

 der specimens have been borrowed wherever they could be got, and their 

 ownership is given in the printed descriptions. 



The fossils in the New Jersey marls attracted the attention of natural- 

 ists at a very early day; Dr. S. G. Morton and Prof L. Vanuxem, of Phil- 

 adelphia, described some of them in the sixth volume of the Journal of the 

 Academy of Natural Sciences in 1828-29, and in the seventeenth voliime of 

 the American Journal of Science in 1 830, and since that time many additions 

 have been made to the number described by others, whose names will ap- 



