THE CLASSIFICATION OF THE UPPER CRETACEOUS 

 FORMATIONS AND FAUNAS OF NEW JERSEY 1 



STUART WELLER 

 The University of Chicago 



Since the organization of the present Geological Survey of New 

 Jersey, three classifications of the Cretaceous formations of the state 

 have been proposed and have been published in the reports of the 

 Survey. The first of these, elaborated by Professor Cook during 

 his administration as state geologist, was published in 1868. 2 At 

 that time the practice of naming geological formations by geographical 

 names was not usually adopted by working geologists, and the suc- 

 cessive beds were designated by names suggested by their lithologic 

 characters. Above the "plastic clays" since known as the Raritan 

 formation two major series of beds were recognized, the "clay-marl" 

 series below and the "marl" series above. The discrimination of 

 the beds of the "marl" series, as first described by Cook, has not 

 been changed by any of the more recent investigations, but a closer 

 study of the "clay-marl" series has led to the discrimination of a 

 series of beds not recognized by Cook. In his interpretation of the 

 stratigraphy of the southern portion of the area, however, Cook, in 

 the absence of accurate topographic maps, fell into one error on 

 account of his failure to recognize the disappearance of his "red 

 sand" formation in that direction, and the consequent continuity 

 of the "lower" and "middle" marl beds. To the south he identified 

 a bed now known to belong in the "clay-marl" series, with the "lower 

 marl" of Monmouth County, and considered the bed now known to 

 represent the combined "lower" and "middle" marls, to be the 

 continuation of the "middle" marl alone. 



In 1 89 1 Professor W. B. Clark entered upon a study of the Cre- 

 taceous beds of New Jersey, and the results of his work are published 

 in the Annual Reports of the Survey for 1892, 1893, and 1897. The 



1 Published by permission of the State Geologist of New Jersey. 



2 Geology of New Jersey, 1868, p. 241. 



7i 



