. Bulletin - New York State Museum. Science. .BEEKMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 451 of the cameras. Surface smooth, internal surface of outer wall marked with fine engirdling lines. Position and localities. Frequent in the Fort Cassin beds at Fort Cassin; rare in the same beds at Valcour N. Y. (A3 of section). Observations. This species is one of great mor- phologic and phylogenetic interest in many respects. The most important of these is the presence of in- terior annulations (or constrictions) upon the â¢conch which have not yet had any effect upon the outer side of the co
. Bulletin - New York State Museum. Science. .BEEKMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 451 of the cameras. Surface smooth, internal surface of outer wall marked with fine engirdling lines. Position and localities. Frequent in the Fort Cassin beds at Fort Cassin; rare in the same beds at Valcour N. Y. (A3 of section). Observations. This species is one of great mor- phologic and phylogenetic interest in many respects. The most important of these is the presence of in- terior annulations (or constrictions) upon the â¢conch which have not yet had any effect upon the outer side of the conch, the lat- ter showing only in exceptional cases, faint transverse elevations upon the liv- ^9 -° ing chamber \see fig. 7, 81. These in- ^''s- ^9 w?-^7F°^^x^' cornu- o I- &/'j oryx Whitf. (sp.) Transverse sec- ternal constrictions have been mistaken t'°"- ^""â 'f,^'%^- /?^; ^° f^"^^- Enlargement (X4) of siphuncle hy Whitfield for external annulations of the conch and the species described as strongly annulated. The form of the supposed annulations as they appear upon the inner cast of the conch is however greatly dift"erent from that of the true annu- lations of most orthoceratites and has led to the specific name. Note on the nautilicones of the Beekmantown and Chazy formations Professor Whitfield has described among the Fort Cassin fossils two species of Nautilus, viz, Nautilus k e 11 o g g i and N . ? champlainensis. Since we have a considerable number of specimens from the \'alcour outcrops, which clearly fall within the boundaries of these species, we have to occupy ourselves with the vicissitudes of the latter. Schroder pointed out soon after the pub- lication of the species [1891, p. 27] that the original description and the drawings of the first named one do not agree with each other and that it is to be inferred that specimens which have not been figured were used for the description. Since the former of these drawings [/.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectscience, bookyear1887
