The Triassic cephalopod genera of America

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Govt. Print. Off., 1905 - Nature - 394 pages
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Page 11 - Very respectfully, CW HAYES, Geologist in Charge of Geology. Hon. CHARLES D. WALCOTT, Director United States Geological Survey.
Page 395 - SLIPS. [Mount each slip upon a separate card, placing the subject at the top of the second slip. The name of the series should not be repeated on the series card, but the additional numbers should be added, as received, to the first entry.] Bain, H[arry] Foster, 1872.
Page 391 - The serial publications of the United States Geological Survey consist of (1) Annual Reports, (2) Monographs, (3) Professional Papers, (4) Bulletins, (5) Mineral Resources, (6) Water-Supply and Irrigation Papers, (7) Topographic Atlas of United States — folios and separate sheets thereof, (8) Geologic Atlas of the United States — folios thereof.
Page 190 - ... umbilical shoulders of the inner whorls. The height of the whorl is a little more than one-half the total diameter, the width is about one and a half times the height, and the whorl is indented to one-third of its height by the inner volution. The width of the umbilicus is a little more than one-fifth of the total diameter of the shell. The surface is ornamented with fine but distinct umbilical knots, from which fine dichotomous ribs curve forward up the sides ; there are also very fine spiral...
Page 21 - Hedenstraemia sp. nov., Clypites sp. nov., Ussuria two new species, and Nannites sp. nov. Besides those here listed there were found several new genera of the same families. This fauna is intimately related to the Lower Triassic faunas of India and eastern Siberia, with several species that may even be identical with those from Asia. It contains several genera hitherto known only from the Lower Trias of India, and others previously found only in the Propty1 The new genera and species of this fauna...
Page 63 - Plate XLVI, Fig. i ; Plate XLVII, Fig. 1. 1893. Tropites {Paratropites) dittmari, Mojsisovics, Cephalopoden der Hallstatter Kalke, II, p. 245, pi. cxv, fig. 4. Involute, discoidal, laterally compressed. Whorls deeply embracing, and deeply indented by the inner whorl. Sides flattened-convex, with abruptly rounded umbilical shoulders, and rather gently rounded abdominal shoulders. Venter narrow and arched, surmounted by a central keel with distinct marginal furrows. The umbilicus is narrow, almost...
Page 21 - ... a reference to either Paleozoic or Mesozoic. But the geologists that described the fauna of the doubtful beds have almost unanimously referred them to the Lower Trias, and this must be the final verdict. The fauna of the Meekoceras beds of Idaho and California is most intimately related to that of the Ceratite marls and the lower part of the Ceratite sandstone of India, with most of the genera in common, and several species that seem to be identical. And although the writer has searched carefully...
Page 182 - Cross section trapezoidal, wider at top. Sides flattened, sloping outward. Abdominal shoulders abrupt and square, venter flattened and broad. The height of the whorl is less than one-third of the total diameter of the shell ; the width is slightly greater than the height ; and the indentation is only one-ninth of the height. The width of the umbilicus is three-sevenths of the total diameter of the shell. The surface is ornamented with coarse ribs that start from a row of knots on the umbilical shoulders...
Page 171 - ... these knots, however, are not set close together as in Balatonites and Trachyceras. The septa consist of rounded saddles and serrated lobes, and in the more specialized forms even the saddles may be denticulated. The external lobe is divided by a siphonal saddle into two narrow branches; there are two laterals, and a series of several small auxiliaries, which may be reduced to mere denticulations of a nearly straight saddle. The internal (antisiphonal) lobe is long, narrow, and bifid, flanked...
Page 208 - The surface is smooth, there being no ornamentation except the exceedingly fine radial striae of growth, which bend backwards on the venter, forming a broad hyponomic sinus. The septa are sinuous, showing both lobes and saddles. The broad and deep ventral saddle is divided by a narrow and shallow abdominal lobe; the lateral lobe is long and rather broad; on the umbilicus there is a second lateral lobe, shallow and broad.

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