Map point data provided by iDigBio.
- C5 Sequence (Waynesville)
Identification in Hand Sample
Modiolopsis versaillensis from the Arnheim Formation of Mt. Orab, Ohio (OUIP 1185)
- (In reference to “Modiolopsis versaillensis.” Cincin. Quart. Journ. Sci. vol. i. p. 150, figs. 18, 19.):
Describes a species of Modiolopsis, which he believes to be new. It is stated to differ from M. modiolaris in having more prominent and angular beaks, and a different hinge-line and ligamentary attachments, and in having the muscular impression placed further in front of the beak. It is from the Cincinnati group of Versailles, Indiana.
- Equivalve, inequilateral, oblong, expanded and compressed posteriorly; basal margin contracted or arched upward, below the beaks; cardinal line straight; beaks near the anterior extremity, and slightly more prominent than those of the Modiolopsis modiolaris; umbones subangular and extending obliquely, posteriorly; surface marked by concentric lines; muscular impression circular and deep, below and anterior to the beak; mesial ridge between it and the umbonal cavity; hinge line plain and smooth, except a slight ligamental depression below the beak. Length of specimens examined varying from 3/4 inch to 2 1/2 inches; breadth and thickness in proportion to length. This species differs from the Modiolopsis modiolaris, in having a more prominent beak, more angular umbones, different hinge line, and ligamentary attachments, and in having the muscular impression farther anterior to the beak. Casts of the two species might not be distinguishable from each other. This species was found by me at Versailles, Indiana, about 300 feet below the rocks of the Upper Silurian, and associated with Anomalodonta gigantea, Anodontopsis (?) Milleri, Pleurotomaria tropidophera, Telinomya occidentalis, etc.