101 



and partly covered by the matrix, which has since been removed. 

 Figs. 2 and 2a are different views of a fnignient, which consists of one 

 of the earliest volutions, evidently not far from the nucleus, and fig. 3 

 is a part of the shell which corresponds very nearly to the piece 

 described by Morton as Ammonceratites Conradi. The specimens are often 

 distorted, yet taken collectively they give a tolerably good general idea 

 of the shape and sculpture of most of the shell. The whorls are rounded 

 and are at first coiled in a dextral and somewhat regular spiral, but the 

 last one is free and partially uncoiled. Those of the spii-e are contiguous, 

 and are enrolled in such a manner as to leave a very deep and moderately 

 wide umbilical cavity which extends nearly to the nucleus. The width 

 of the umbilicus is rather less than one-third that of the greatest 

 diameter of the shell (which measures three inches and a-quarter in the 

 largest specimen,) and it is as wide in proportion in the earliest volution 

 known. The number of whorls in the coiled part was probably about 

 five, and the height of the spire appears to have exceeded its greatest 

 width. The exact direction taken by the free termination of the shell 

 is not yet known. In some specimens, especially in that from which 

 fig. 3 was taken, the whorl suddenly takes a decidedly upward curve 

 apparently just previous to uncoiling, but in another individual (which, 

 however, is obviously distorted) the upward curve is not quite so 

 strongly marked and it subsequently seems to slope convexly down- 

 wards again. 



The surface is marked by rather distant, prominent and very acute, 

 transverse ribs, which are much narrower than the rather deeply concave 

 grooves between them. The ribs are flexuous above and comparativelj'' 

 straight on the lower or umbilical face: in most specimens they are 

 both simple and parallel, but in one example some of the cost© bifurcate 

 near the middle of the sides. Septum unknown. 



The writer has long been convinced that the fossils described above 

 are specifically identical with the New Jersey Heteroceras described 

 and figured by Morton under the name Ammonceratites Conradi., and Mr. 

 G. "W. Tryon, who has compared the two best Maple Bay specimens (the 

 originals of figures 1 and 3 of plate 12) with Morton's type of A. Conradi, 

 and with another cast of the same species, from Shell Town, N. J., labelled 

 by Mr. Conrad, both in the Museum of the Academy of Natural Sciences 

 of Phi+adelphia, has come to the same conclusion. In a letter, dated 

 Mai-ch 5th, 1878, Mr. Trj-on says: '* I have carefully compared your 

 specimens of Htteroceras with our tj'pes and find no diffeience which 

 oannot be assigned to oomprossion. Tho I'iba on youx* specimens are 



