. Bulletins of American paleontology. Oregon Oligocene Turridae: Hickman 51. Text-figure 10. — Comparative anal sinus configuration in Paleogene species of Surculites and Nekcivis from camera lucida tracings of growth lines ad- justed to uniform shoulder height. Heavy lines denote posterior and anterior sutures, light line denotes periphery, and dashed line denotes apex of sinus, a. S. mat/iewsonii (Gabb) ; b. N. luashingtoniana (Weaver) ; c. A'^. io (Gabb) ; d. A'^. cf. A'', nehalemensis (Anderson and Martin) ; e. A^. nchalemensis (Ander- son and Martin). Other from the Twin River Formation i
. Bulletins of American paleontology. Oregon Oligocene Turridae: Hickman 51. Text-figure 10. — Comparative anal sinus configuration in Paleogene species of Surculites and Nekcivis from camera lucida tracings of growth lines ad- justed to uniform shoulder height. Heavy lines denote posterior and anterior sutures, light line denotes periphery, and dashed line denotes apex of sinus, a. S. mat/iewsonii (Gabb) ; b. N. luashingtoniana (Weaver) ; c. A'^. io (Gabb) ; d. A'^. cf. A'', nehalemensis (Anderson and Martin) ; e. A^. nchalemensis (Ander- son and Martin). Other from the Twin River Formation in Washington (Text-figure 1). A specimen from the Lincoln Creek Formation represents a third provincial Oligocene occurrence of this species in Washington. Shell material is well preserved, but the specimens are broken and crushed or distorted. In addition to the broad shallow anal sinus, the species exhibits a characteristic sharply keeled periphery and tabular whorl profile. The body whorl is divided by a second weaker carination that does not appear on the spire whorls which are parallel to the axis of coiling anterior to the periphery. Material exaviined. — Three specimens. Stratigraphic distribution. — Surculites sp. is restricted to the provincial Oligocene Turritella porterensis and Echinophoria rex zones (Text-figure 6). Figured specimen. —VS>'NU 216414. (USGS M1729. Lincoln Creek Formation). Other localities. — Twin River Formation: UCMP A3690. Mar- rowstone Shale: UCMP 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 Paleontological Research Institution (Ithaca, N. Y. ); Columbia University. Ithaca, N. Y. , Paleontological Research Institution [etc. ]
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