Part II - State of New Jersey

202 CRETACEOUS FOSSILSgins. Hinge and teeth typical of the genus as exemplified by Brevlarcaminor Stephenson from the It'oodbine of Texas, except that there area few more hinge teeth.I~reuiarca rul~lei differs from B. nti?ior in that its sculpture showsno cross-hatching or radiating markings.Dimensions: Length 3.9 mm. ; width 5.1 mm.; thickness 1.8 nlm.Locality: Boring 16 (1648) feet RARITAN formation.Iiolotype: ANSP 30489; also ten paratypes.Named in honor of James 1,. Ruhle. vho assisted in the preparationof the cores for study.Idonearca (?) harrirvillensis Richards n. sp.Plate 93, Fignres 8, 9, 12Shell of mccli~un size, rather thick, snbtrapezoidal, strongly convex,ineq~~ilateral, presum;lbly equiralvo. Anterior margin flattened witha distinct keel. Posterodorsal slope is moderately steep ; ventral marginbroadly rounded. Cardinal area roughly tri:lngular, elongate, withabout six wavy, chevron-like lines. Hinge slightly curved. The medialteeth are small and irregular; the lateral teeth are coarse, about fiveon each side, are longer and coarser, irregularly oblique, becominghorizontal at the ends. Umbonal ridge subangular. Beaks moderatelyprominent, broadly ineurved, sitnated about one-third the length of theshell from the anterior extremity. M:usele scar not visible. Ornamentationlimited to fine concentric ribs at varying distances from each other,wit.h a very faint indication of cross-hatching on some of the interspaces.Idonenrcn (7) har~risz.il/ensis differs from I(7onearca blanpiediStephenson, known from the \l'oodhine formation of Texas and theRaritan formation of New Jersey, in its general shape, and by thepresence of a pronounced keel on the anterior margin. Because of theineonlplete nature of the shell, it does not appear wise to refer it definitelyto the genus Zdonearca.IIolotype and numerous brokcn specimens.Dimensions: Length 14 mm.; width 20 mm.; thickness 6 mm (holotype).Ilolotypc: ANSI' 30443.Locality: Boring 1.6 (1648 feet) :&\RITA;\' formation.Ostrea ratitanensis lliehards n. sp.Plate 93, Fignres 13, 14Shell small, laterally areuate. IIinge-line slightly curved. Shellmarked with from seven to ten deep plieations which extend inwardfrom the lower or convex margin but do not reach the opposite side.NEW JERSEY GEOLOGICAL SURVEY