TURTLES OF JUDITH RIVER FORMATION 53 



probable that had better material been at the disposal of Doctor 

 Leidy he would have found them to be at least specifically distinct." 

 Specimens identified by Cope as Trionyx foveatus were collected 

 by Sternberg in the Judith River area in 1876; it does not appear to 

 have been found by Stanton and Hatcher when they visited the 

 area in 1905. This species was reported by Marsh from the "Cera- 

 tops beds" near Denver, Colorado, but according to Hay these 

 specimens "belong probably to Aspideretes beecheri" a species from 

 the Lance formation of Converse County, Wyoming. Trionyx 

 foveatus has also been identified by Lambe from the Belly River 

 beds of the Red Deer River region in Canada, and by Barnum Brown 

 in the "Hell Creek beds" (= Lance formation) of Montana. 



From this review it appears possible that there are two and quite 

 likely three species confused under the name of Trionyx foveatus, 

 and hence any conclusion as to which part of the "species" belongs 

 to the Judith River, and which to the Lance formation, must be a 

 matter of more or less doubt. 



2. Trionyx vagans Cope [Aspideretes? vagans (Cope) Hay]. 



Type locality: Bijou Basin (Bijou Creek), 40 miles east of Den- 

 ver, Colorado, in beds regarded by Cross as probably Arapahoe in 

 age. It was also reported by Cope from near the mouth of the 

 Bighorn River, Montana, and near Long Lake, North Dakota, 

 both localities in beds belonging in all probability to the Lance 

 formation. Apparently on the basis of Lambe's reporting it from 

 the Belly River beds of the Red Deer River in Canada, it was in- 

 cluded by Hatcher in his list of Judith River species, though Hatcher 

 himself points out the obvious distinctness between the type speci- 

 mens and the specimens so identified by Lambe. Hay has referred 

 Lambe's specimens to another species, and hence all pretense of 

 Trionyx vagans as a Judith River species disappears. 



3. Plastomenus coalescens Cope. [Aspideretes coalescens (Cope) 



Hay]. 



Type locality: "Bad Lands south of Woody Mountain, latitude 

 49 ," longitude about 106 , Assiniboia, Canada. 



