226 TRANSACTIONS OF THE [MaY 22 



ber of the Cretaceous Group [New Jersey Marl] underlies Long 

 Island, and may be a continuation of the great range wliicli 

 begins at the south, in Virginia, and runs throngh New Jersey 

 to the Neversink Hills, at which place it is last seen above the 

 surface." 



This same Exogyra is also quoted by several subsequent 

 writers, long after it had lost its importance as an indication of 

 the presence of cretaceous strata, by reason of the discovery of 

 other indisputable cretaceous material in situ. The latest 

 reference is b}' C. A. White*, who, following the early conclu- 

 sions of E. D. Copef, had divided the eastern cretaceous strata 

 into "marine" and "non-marine." He says: "All the 

 admissible evidence of the present existence of cretaceous 

 deposits upon Long Island relates to the non-marine division 

 alone. If the reputed discovery of a specimen of Exogyra 

 costata, Say, in digging a well near Brooklyn were satisfactorily 

 confirmed, and it were shown to have been found in situ, the 

 fact would be accepted as proof of the present existence there 

 of at least a portion of the marine division." 



The probable extension eastward and northward of the strata 

 composing the coastal plain was noted by Edward Hitchcock in 

 1824, in a paper entitled " Notices on the Geology of Martha's 

 Vineyard and the Elizabeth Islands "|, where he says : 



" Long Island, in those places where I have seen it, is unques- 

 tionably very similar in its geological structure to Martha's 

 Vineyard, and probably belongs to the same era. . . If we 

 take [Maclure's] map, and prolong the line, or rather curve, 

 that separates the alluvial tract . . from the primitive 

 towards the northeast, we shall find that it passes between 

 Martha's Vineyard and the continent . . leaving us to con- 

 clude that the Vineyard and Nantucket are the continuation of 

 that extensive formation, hitherto called Alluvial, of which Loug 

 Island has been regarded the northeastern limit.'' 



Subsequently, the same author notes the occurrence near 

 Marshfield, Mass., of material similar to the greensand or marl 

 of New Jersey§, and also suggests the probable cretaceous age 

 of certain of the strata on Martha's Vineyard||. In this connec- 

 tion should be mentioned the first discovery and description of 



* Bull. No. 82, U. S. Geol. Surv. Correlation Papers— Cretaceous. (1891.) 



I Proc. Acad. Nat. Sci. Phil. xx. 157, 158 (1868). 



+ Am. Journ. Sci. vii. 240-248 (1824). 



§ Kept, on the Geol. of Mass., examined under the direction of the Govern- 

 ment of that State during the years 18H0 and 1831 (Am. Journ. Sci. xxii. i-70 

 (1832). 



II Final Rept. on the Geol. of Mass., vol. ii. pp. 429, 43o, PI. 19, figs. 1-5. (isii.) 



