. Annual report of the regents of the university of the state of New York on the condition of the State Cabinet of Natural History and the historical and antiquarian collection annexed thereto. Discina alleghania. CRANIA HAMILTONI^ ( ). Shell subconical, subcircular; apex subcentral, pointed in well-preserved speci-mens, often worn or decorticated. Exterior surface of the dorsal or upper valvelamellose. Ventral or lower valve marked by four strong muscular impressions,which are variable in form: the two lateral ones are distant, and each apparentlydouble; the central impressions approximat
. Annual report of the regents of the university of the state of New York on the condition of the State Cabinet of Natural History and the historical and antiquarian collection annexed thereto. Discina alleghania. CRANIA HAMILTONI^ ( ). Shell subconical, subcircular; apex subcentral, pointed in well-preserved speci-mens, often worn or decorticated. Exterior surface of the dorsal or upper valvelamellose. Ventral or lower valve marked by four strong muscular impressions,which are variable in form: the two lateral ones are distant, and each apparentlydouble; the central impressions approximate, diverging above and assuming asomewhat cordiform appearance; vascular impressions strongly species is found adhering to valves of Tropidoleptus, Strophodonta, Spirifer, Spirigera, ^vicula, Orthoceras; and the separated valves are free in the formation and localities. In the shales of the Hamilton group : Western New-York, Maryland, and Virginia. CONTRIBUTIONS TO PALAEONTOLOGY. • 183 CRANIA CRENISTRIATA (). Ventral or upper valve very depressed conical, subcircular in outline; apex cen-tral or subcentral, a little inclined. Surface marked by sharp
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectscience, bookyear1853
