REVIEW OF PREVIOUS INVESTIGATIONS. 321 



the greensand series of New Jersey was of later age than the Cretaceous, 

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



The earlier state surveys having come to an end, a considerable period 

 elapsed during which the several states of the district under considera- 

 tion were without official organizations. In 1847 Maryland made pro- 

 vision for a state agricultural chemist, while a few years subsequently 

 to this the state of New Jersey established a second geological survey. 

 Under the direction of the first agricultural chemist, Dr James Higgins, 

 little geological work was attempted in Maryland, but the survey of New 

 Jersey, under the direction of William Kitchell, had as assistant geolo- 

 gist George H. Cook, who was later to become himself the head of the 

 survey, and in that capacity to add more to the knowledge of the stratig- 

 raphy of the Cretaceous formations than any one who had preceded 

 him. In the first of Kitchell's reports for the year 1854, Cook already 

 recognized the fact that " there are three distinct beds of marl." These 

 three marl beds were examined by him with much care and the char- 

 acteristic features of each portion of them described in the later Survey 

 reports. 



During the decade 1860 to 1870 many special articles dealing with 

 the paleontology of the several formations under consideration appeared, 

 although most of these publications are confined to the New Jersey por- 

 tion of the region. Conrad, Cope, Marsh, Credner, Gabb, Meek, and 

 others contributed to the same, with the result that a fuller knowledge 

 was gained of the paleontology of the New Jersey area than of any other 

 Cretaceous district throughout the Coastal plain. 



In 1860 Dr Philip T. Tyson, who had been appointed state agricult- 

 ural chemist to succeed Dr James Higgins, published his first annual 

 report upon the geology of Maryland, in which he discusses the Creta- 

 ceous formations of that state. His second and last report appeared in 

 1862. Although he recognized the presence of some of the New Jersey 

 divisions upon the eastern shore of Maryland, he made little attempt at 

 their accurate discrimination. 



Professor George H. Cook, having been appointed state geologist of New 

 Jersey, presented his first report of progress for the year 1865. Reports 

 were published during successive years until his death, in 1889. Asso- 

 ciated with him in much of his work was Professor J. C. Smock, the 

 present head of the survey. It is unnecessary at this time to view the 

 advance made each year or to refer in detail to each report. In 1868 a 

 general volume appeared, entitled "Geology of New Jersey," in which 

 an extensive description of the Coastal Plain deposits is found. In this 

 report Professor Cook divided the Cretaceous deposits as follows : 



