OF THE UNITED STATES. 15 
cially in some places overlaid by deep deposits of clay 
and sand, as at Bordentown, White Hill &c. In other 
localities, the older Pliocene (Upper marine) overlies 
the secondary, as is the case a few miles from Salem. 
Above all these deposits is mostly found a uniform covering 
of gray sand, referred by Mr. Vanuxem to alluvial ori- 
gins yet we often observe the marl, with its peculiar 
fossils, immediately beneath the soil. 
These fossils, as will hereafter be shown, are of a very 
striking character, occasionally grouped in vast numbers, 
and in other instances almost wholly absent. The genera 
Gryphea, Exogyra and Belemnites, are found abun- 
dantly throughout. Near Egypt, on the margin of Cross- 
wick’s creek, and at Ralph’s mill, near Hornerstown, 
Terebratule occur in prodigious numbers, but under 
different appearances: at Egypt, for instance, is a series 
of thin strata, some filled exclusively by Terebratule, 
others by Gryphza, so disintegrated as mostly to fall to 
pieces on removing them from the marl. Near Horners- 
town, on the contrary, the Terebratule are found in a 
very indurated matrix in the bottom of a rivulet, and in 
perfect preservation. Near Walnford, Exogyre and 
Belemnites predominate: at Arneytown, these genera 
are associated with Ammonites, Baculites &c. The 
marls of the whole of Monmouth county are similarly 
characterized, especially those near Middletown, the 
Nutt swamp &c. 
Mullica hill, in Gloucester, presents a naked elevation 
of forty or fifty feet, composed of sand and small quartz 
