DESCRIPTIONS OF INVERTEBRATE FOSSILS. OO 



III Marcy's Red River Report (p. 19'3, PI. G, fig. 2),Shuinard 

 describes and figures an Inoceranins that "occurs rather 

 abundantly at Camp No. 4, Cross Timbers, Texas," referring 

 it to I. couferiim-dunulafus, Roem. That his description 

 and figure rehite, not to the upper Cretaceous coiifertini- 

 annulafiis, but to the species which I have here named 

 /. conuiticheiuui, is indicated not only by the figure that he 

 gives but also by the fact that the stratigraphic source of all 

 of the fossils that he described from " Cross Timbers, Texas," 

 was evidently the middle part of the lower Cretaceous; i. e., 

 the Comanche Peak limestone and the Duck creek (lower 

 Washita) limestone. Nearly all of these fossils are com- 

 mon in, and chiefly characteristic of, the Comanche Peak 

 limestone; but the association of Schloeuhachia peruviana, 

 Von B., with Pachydiscus marcianus, Shum.,* which he men- 

 tions, is a feature of the Duck creek horizcju and indicates 

 the presence of this horizon there also, and hence the j)rob- 

 able presence there of the common Duck creek fossil, Inoce- 

 ramus comancheana. 



Inoceramus munsoni, sp. nov. 



Shell ( ?inequi valve), elevated, obliquely triangular-ovate, 

 of moderate convexity; hinge short; beak of left valve elevated 

 high above the hinge-line, strongly flattened on its right 

 (inner) anterior quarter, its apex incurved as in /. siilcatus, 

 Park.; valves extremely thin, moulded with small, feebly ex- 

 pressed, concentric undulations and striae and, on its anterior 

 third, with three large and prominent, wave-like, radial folds, 

 the foremost and shortest one of which forms a sort of shoul- 

 der in advance of which the border of the shell is strongly 

 inflected to form the flat ante-umbonal area, the part of the 

 valve posterior to these three folds, presenting two broad, 

 obsolescent, low-convex, radial segments, the posterior one of 

 which may be subdivided into two narrow folds. 



Measurcmcnis. — Of a left valve; height 57, length 58, 

 convexity 23, axis of greatest dimension (57 mm.; of a smaller 

 left valve, height 36, length 33, convexity 11 mm. 



*His Amrtionites acuto^carinatus and Ammonites marciana. See 1. c, p. 197. 



