Miscellaneous Documents: 30th Congress, 1st Session - 49th Congress, 1st Session, Volumen38


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Página 229 - Aviculopecten in form, hinge furnished with a series of small cartilage pits throughout its entire length.
Página 3 - ... similarity of the three species so widely separated in geologic time (Plate xxi, figs. 18, 19, 20). The fauna of the White Pine shale in the White Pine District is in many respects a peculiar one, combining as it does species ranging from the Middle Devonian into the Lower Carboniferous. The stratigraphic position of the shale is at the summit of the Devonian system and at the base of the Carboniferous; it is overlain in the Eureka District, where the section is unbroken, by a massive belt of...
Página 228 - ... sinus beneath the ear, the ear joining the body of the shell higher up towards the beak. The posterior ear is either very short and small, or obsolete, being merged into the flattened posterior umbonal slope. Hinge-line very short. Beaks small, the sides sloping away at an angle of about 80 degrees. Surface of the larger shells smooth or with fine concentric striae and lines of growth ; a few very indistinct fine radii are present towards the lower margin ; the anterior ear of the right valve...
Página 229 - Surv. 1ll., vol. ii, plate xxvi, fig. pa) is the only American species that has been referred to the genus. It differs very materially in form and surface characters from the species under consideration. Formation and localities. — Lower portion of the Carboniferous Group in the canon north of Pinto Peak; on the west slope of Richmond Mountain, and in the canon south of a small conical hill on the east side of Secret-canon-road Canon, Eureka District, Nevada.
Página 2 - ... a sparse fragmentary fauna which closely resembles in general character the fauna of the similar upper Devonian black shales of the eastern continental area. In these western sections there is a remarkable difference in the range and habit of species. " Some species," as Mr. CD Walcott has shown, "have reversed their relative position in the group as they have been known heretofore, and others have a greater vertical range.
Página 1 - Quebec group or the Calciferous and Chazy groups, is of special interest. The transition from the Cambrian to the Silurian fauna is very gradual, and such as would occur where there was no marked physical disturbance to influence the...
Página 3 - Claclopora pulchra, Syringopora Hisingeri, and Cyathophyllum corniculum, of the great Corniferous coral reef of the east, occur at the upper horizon, and Syringopora perelegans, of the same formation in New York, ranges throughout the group in Nevada. The occurrence of rare species and those of limited range in the eastern Devonian is not an unusual feature, as we find Lingula Lcena, Strophodonta Pater soni, Chonetes hemispherica, Productus tnmcatus, etc.
Página 56 - ... eyelobes; greatest width fivesixths of the length. Glabella broadly conical, rounded in front, and moderately convex ; marked by a pair of short posterior furrows. Occipital ring narrow, rounded, separated from the base of the glabella by a narrow, distinct occipital furrow; fixed cheeks rather narrow; palpebral lobes small, and situated opposite the central portion of the glabella; frontal limb expanded, its length equaling more than one-third the entire length of the head; concave from the...

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