Chesapecten septenarius (Say, 1824)
SAY, T. 1824. An account of some of the fossil shells of Maryland. Journal of the Academy of Natural Sciences of Philadelphia, 4 (1): 124-155. [p. 136, pl. 9, fig. 3]
T. Say, 1824, plate 9.
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«Shell convex, suborbicular: auricles subequal: surface with numerous slightly scaly striae, and about seven remote ribs, of which the three intermediate ones are much elevated, rounded, or slightly flattened on the top.
Length nearly two inches and seven-tenths. But a single imperfect, inferior valve, occurs in Mr. Finch's collection; but this is so perfectly distinct from any other that I have seen described, that I have no hesitation to describe it as new. The stme are equally distinct OD the ribs, and in the intermediate spaces. The scales are ratha' thick, very small, and not confined to the strim, but are also pbservable in the spaces between the strim.» THOMAS SAY, 1824
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«Description: Shell large, subcircular, very heavy; right and left valves convex, well inflated; ribs 4 to 12, wide, squared or laterally expanded at the crest; ribs with secondary sculpture of fine striations, scaling weak at edge of ribs, or lacking.
Occurrence: Pliocene. Virginia - Yorktown, lower and middle Zone 2; Carolinas – Yorktown, lower Zone 2, lower and upper Goose Creek Limestone, Raysor; Florida – Tamiami Limestone and lower Jackson Bluff. Type locality: "Maryland" [unknown Virginia locality]. Discussion: Chesapecten septenarius is a highly variable species, similar in some of its morphologies to the older to contemporaneous Chesapecten jeffersonius. Chesapecten septenarius has between four and twelve ribs that vary in cross-section between "T" topped, square, and slightly rounded morphologies. Chesapecten jeffersonius typically has seven to nine lower, rounded ribs. The latter is more characteristic of deposits below the Goose Creek Limestone, such as the Zone 1 Yorktown Formation to the north, or the Wabasso beds. However, Stanley (1988, personnal communication) has paired specimens of C. jeffersonius from the Tamiami Formation (bed 11, APAC pit, Sarasota, Florida), a formation that is faunally equivalent to the lower Goose Creek Limestone. Sloan specimens from "Raysor's Bridge" figured
by Ward and Huddlestun (1988) seem to conform with C. jeffersonius morphologies. We have found no such specimens in either the Goose Creek or Raysor levels at the Berkeley Quarry. Pooser (1965, p. 23) and Colquhoun (1965, p. 46) reported Chesapecten jeffersonius from a pond near Orangeburg, but subsequent collections from the site contain only Chesapecten septenarius.» CAMPBELL, M. R. & L. D. CAMPBELL. 1995. Preliminary Biostratigraphy and Molluscan Fauna of the Goose Creek Limestone of Eastern South Carolina.Tulane Studies in Geology and Paleontology, 27 (1-4): 53-100, pls. 1-5. [p. 78, 80]
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Chesapecten septenarius (Say); M. R. Campbell & L. D. Campbell, 1995, Preliminary Biostratigraphy and Molluscan Fauna of the Goose Creek Limestone of Eastern South Carolina, plate 1, figures 4, 6; plate 3, figure 5.
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«Occurrence.—The type locality is Virginia, probably from the James River near City Point or the York River at Yorktown.
Additional Virginia localities (Yorktown Formation Zone 2 of Mansfield) include Petersburg (first 6 ft (1.8 m) above Virginia St. Marys Formation contact with Zone 2 Yorktown) (map loc. 39; USGS loc. 25328), 2 miles (3.2 km) above Yorktown (fig. 1, loc. 40; USGS loc. 25329), Rices Borrow Pit (fig. 1, loc. 41; USGS loc. 25330), Cobham Wharf (top shell bed) (fig. 1, loc. 42; USGS loc. 25336), Kings Mill Wharf (fig. 1, loc. 43; USGS loc. 25332), Lee Creek mine pit (fig. 1, loc. 45; USGS loc. 25334). Comments.— The specimen figured here (pl. 6, figs. 5, 6) was obtained from the British Museum. It agrees almost exactly with Say's figured specimen, including the large breaks in the shell margin. The specimen is labeled "N. Amer." Say apparently had only one specimen.» WARD, L. W. & B. W. BLACKWELDER. 1975. Chesapecten, a new genus of Pectinidae (Mollusca: Bivalvia) from the Miocene and Pliocene of eastern North America. United States Geological Survey Professional Paper, 861: 1-24, pls 1-7. [p. 16]
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Chesapecten septenarius (Say); L. W. Ward & B. W. Blackwelder, 1975, Chesapecten, a new genus of Pectinidae, plate 6, figures 5-7; plate 7, figures 2, 9.
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