Box 26, Folder 1: Paleontology Draft 7: AcePhala I

Lower Silurian-Trenton Limestone

Watertown, Jefferson Co. N.Y.

Genus Amphidesma, Lamarck; DeKay, Nat. Hist. N.Y. p. 237 P 3p 416

Shell inequilateral, transverse, suboval, or somewhat rounded; sides slightly gaping; hinge with one or two cardinal teeth, and a narrow groove for the internal ligament; external one short; internal one fixed in the internal grooves.

Gr. external and internal ligament

Amphidesma aegualis, [Conrad] Say, Jour. Acad. Nat. Sc, vol 2 p 308; Conrad Med. Ter. Foss p 76 pl 43 fig 9

Suborbicular, sentricose, smooth; beaks subundial, nearest the posterior end; umbonical slope submarginal, slightly carinated; posterior side somewhat warped or bent; lateral teeth in the right valve only, remote; linear. L. 0.4 H 0.3

Medial Tertiary Wilmington N. Car.

Amphidesma aequata, Conrad Medial Ter. Foss. p. 65 pl 36 fig 5

Longitudinally oval, convex with 17 laminated concentric striae; anterior & posterior margins nearly equally rounded; basal margin very regularly rounded; beaks slightly prominent; one cardinal tooth in the right valve, & no lateral teeth. L. 0.3 H 0.25

Medial Tertiary

Wilmington N. Car.

Amphidesma carinata, Conrad, [Ter. Foss] Jour. Ac. Nat Sc. vol 6 p 229 pl 9 fig 23; Medial Tertiary Foss. p 37 pl 19 fig 7

Shell ovate-oval, compressed; beaks rather posterior to the middle, slightly prominent; surface with fine crowded regular concentric striae, and others more profound and remote; submargin with an obsolete obtuse undulation; lateral teeth in the right valve; in the left, none.

A. carinata, nob. Jour. Acad, Nat. Sc., vol. vi p. 229, pl ix. fig. 23.

Locality. St. Mary's river, Maryland, in blue clay.

L. 0.9 H 0.65

Medial Tertiary

St Mary's river Maryland, in blue clay.