. Gasteropoda and Cephalopoda of the Raritan clays and greensand marls of New Jersey. Gastropoda, Fossil; Cephalopoda, Fossil; Paleontology. CEPHALOPODA OF THE OKETAOEOUS MARLS. 259 of three chambers, retaining two lobes and two sinuses each of two of them, and a single lobe and sinus of the third; the other fragment, a cast of several lobes and sinuses of chambers from near the umbilicus. They represent a specimen of large size, probably not less than 7 or 8 inches in Fig. 1.—Placenticeras (Sphenodiscus) lenticulare (Owen) Meek. (From U. S. Geol. Surv. Terr., vol. 9, p. 473.) In ex
. Gasteropoda and Cephalopoda of the Raritan clays and greensand marls of New Jersey. Gastropoda, Fossil; Cephalopoda, Fossil; Paleontology. CEPHALOPODA OF THE OKETAOEOUS MARLS. 259 of three chambers, retaining two lobes and two sinuses each of two of them, and a single lobe and sinus of the third; the other fragment, a cast of several lobes and sinuses of chambers from near the umbilicus. They represent a specimen of large size, probably not less than 7 or 8 inches in Fig. 1.—Placenticeras (Sphenodiscus) lenticulare (Owen) Meek. (From U. S. Geol. Surv. Terr., vol. 9, p. 473.) In external features this species is much like Am. (Placenticeras) placerda De Kay, but is a httle more spreading at the umbilicus, although the margin of the volutions are closer together, and it is usually sharply rounded on the back, instead of narrowly flattened as in that one until it is quite well grown, often to a diameter of 7 or more inches^ before it becomes rounded. Owing to the more spreading form of the umbilicus in this one, the point of greatest diameter is nearer to the middle of the width of the volution than hi P, placenta, where it is quite near the inner margin. In the western forms of P. lenticularis there are sometimes very indistinct and 'distant folds on the surface, which radiate from the umbihcus, as shown by Mr. F. B. Meek on his figure in the Invert. Paleont., as above cited, PL xxxiv. Fig. la. I have not seen any indications of such a feature on any New Jersey examples of. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Whitfield, Robert Parr, 1828-1910; New Jersey Geological Survey. [Report on paleontology]. Trenton, J. L. Murphy Pub. Co.
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