174 THE JOURNAL OF GEOLOGY. 



more complete and definite recognition of the several members 

 of the coastal series in which both the Cretaceous and Tertiary 

 formations were described in some detail. 



With the establishment of the official geological survey of 

 New Jersey under the direction of Professor H. D. Rogers^ the 

 first attempt was made at a detailed differentiation of the local de- 

 posits. The formations, beginning at the bottom, were designated 

 as follows : Clays and Sands, Gree?isa?td, Limestone, Ferruginous Sajid, 

 and Brown Sandstojie. Although the various members were not 

 clearly defined and widely different materials were included under 

 the same division, yet the easterly dip of the strata was observed 

 and the broader distinctions in the stratigraphy of the area were 

 recognized. 



Dr. T. A. Conrad,^ in 1848, first suggested that the upper por- 

 tion of the greensand series was of later age than the Cretaceous, 

 a conclusion which he more fully elaborated at a later date. 



The second geological survey of New Jersey, organized in 

 1854, under the direction of Wm. Kitchell, had as assistant 

 geologist, George H. Cook, who a few years later became him- 

 self State Geologist, a position he held for over twenty-five years, 

 until his death in 1889. ^^ devoted from the first much atten- 

 tion to the greensands, and his classification of the strata has met 

 with wide acceptance. It is elaborated in much detail in the 

 Geology of New Jersey, published in 1868. The series of forma- 

 tions as recognized by Professor Cook is as follows, beginning 

 with the oldest : Plastic Clay, Clay Marls, Lower Marl Bed, Red 

 Sa?id, Middle Marl Bed, Yellow Sand, and Upper Marl Bed. Subse- 

 quently, Professor Cook 3 considered that an unconformity existed 

 between the Eocene and Cretaceous members of the Upper Marl 

 Bed. 



There is no area in this country where the several formations 

 have been studied more with reference to their own characteristics 



'Philadelphia Acad. Nat. Sci. Jour. Vol. 6, 1828, pp. 59-71. 



= Philadelphia Acad. Nat. Sci. Jour, new ser. Vol. i, 184S, p. 129. Philadelphia 

 Acad. Nat. Sci. Proc. Vol. 17, 1865, pp. 71, 72. 



3 Report of the State Geologist for 1883, pp. 13-19. 



