THE CRETACEOUS AND TERTIARY FORMA- 

 TIONS OF NEW JERSEY. 



H. B. Kummel. 



THE CRETACEOUS SYSTEM. 



The Cretaceous strata of New Jersey outcrop southeast of 

 a line from Trenton to New Brunswick, and as shown by well 

 borings underlie all of South Jersey, although over most of the 

 area they are deeply buried beneath later formations of Tertiary 

 age and even along their belt of outcrop they are frequently 

 covered with a mantle of sand and gravel of Quaternary age. 



They comprise unconsolidated sands and clays, which dip 50 

 to 25 feet per mile to the southeast, and which have an aggre- 

 gate thickness of from 500 to 1,000 feet, the greater thickness 

 being found in the northern portion of the area. The lower- 

 most beds are referred to the upper part of the Lower Cretaceous 

 and are of non-marine origin. The middle and upper portions, 

 however, belong to the Upper Cretaceous and contain an abun- 

 dant marine fauna. 



Raritan formation. — The Raritan formation is extremely vari- 

 able, consisting chiefly of light-colored sands and clays, some of 

 the latter being highly refractory. There is on the whole a pre- 

 ponderance of clays in the lower, and of sands in the upper, half 

 of the series. Since it was laid down on an irregular surface 

 its thickness is variable, ranging from 150 to 250 feet at the 

 outcrop, but increasing to the southeastward, as shown by well- 

 borings, to over 500 feet. Northeast of Trenton it rests uncon- 

 formably upon the beveled Triassic shales, but farther southward 

 upon the ancient crystallines of early Paleozoic or pre-Paleozoic 

 age, and perhaps at undetermined points still farther south on 

 earlier Cretaceous beds. It dips 40 to 50 feet per mile to the 



(?) 



