320 W. B. CLARK — UPPER CRETACEOUS FORMATIONS OF NEW JERSEY. 



Ill 1835* Dr Morton proposed a general division of the Cretaceous of 

 the United States into three groups, the uppermost of which, however, 

 is now generally regarded as belonging to the Tertiary. His views on 

 this point were again stated in 1842.f 



During the decade 1830 to 1840 the three states of New Jersey, Dela- 

 ware, and Maryland established state geological surveys under the direc- 

 tion respectively of H. D. Rogers, J. C. Booth, and J. T. Ducatel. 



The first attempt at a local and detailed differentiation of the Creta- 

 ceous deposits in the northern Atlantic Coastal plain appears in Professor 

 Rogers' first report, published in 1836, and is more elaborated in his final 

 report, published in 1840, in which he recognizes the following forma- 

 tions, beginning with the lowest : Clays and Sand, Greensand, Limestone, 

 Ferruginous Sand, Brown Sandstone. Although these several divisions 

 were not clearly defined, and widely different materials were included in 

 the same formation, yet the easterly dip of the strata was observed and 

 the broader distinctions in the formation were recognized. 



Ducatel, in his annual report as state geologist for 1837, records the 

 presence of Cretaceous deposits along the Sassafras river on the eastern 

 shore of Maryland, while Booth, in his ''Memoir of the Geological Sur- 

 vey of the state of Delaware," published in 1841, which was based upon 

 his two annual reports for the years 1837 and 1838, divides the " Upper 

 Secondary " of his state into the " Red Clay " and the " Greensand " 

 formations. 



The visit of Charles Lyell to the United States in 1841 was an important 

 event in the history of Coastal Plain geology. The inspiring presence of 

 the author of the epoch-making " Principles of Geology," coupled with 

 his wide knowledge regarding similar deposits in Europe, led to renewed 

 activities in the field of Coastal Plain geology and the correct interpreta- 

 tion, under his leadership, of many points which had up to that time 

 been but imperfectly understood. Although Lyell's work had reference 

 more to the Tertiary than the Cretaceous, yet his observations in several 

 instances were turned either directly or indirectly to the latter. In his 

 contributions X he correlated the American Cretaceous rocks with the 

 divisions between the Gault and the Maestricht of Europe, and also 

 showed that Morton's upper division of the Cretaceous was of Eocene 

 age. 



Dr T. A. Conrad § in 1848 first suggested that the upper portion of 



* Araer. Jour. Sci., vol. 28, 1835, pp. 276-278. 



t Jour. Acad. Nat. Sci. Philadelphia, vol. 8, 1842, pp. 207-227. 



I Quart. Jour. Geol. Soc. London, vol. 1, 1843, pp. 55-60 ; Proc. Geol. Soc. London, vol. 4, 1845, pp. 

 31-33 ; Amer. Jour. Sci., 1844, vol. 47, pp. 213, 214. 



§ Jour. Acad. Nat. Sci. Philadelphia, new series, vol. 1, 1848, p. 129 ; Proc. Acad. Nat. Sci. Phila- 

 delphia, vol. 17, 1865, pp. 71, 72. 



