TURTLES OF JUDITH RIVER FORMATION 6l 



The history of this species is much the same as that of the last, 

 except that specimens identified under this name have a somewhat 

 wider distribution. It was included by Cope in his list of Judith 

 River vertebrates, but, as stated under the last species, was ex- 

 cluded from this fauna by Hatcher. It is accepted by Doctor Hay 28 

 as of Judith River age on the ground that it was found in the region 

 about Milk River, Alberta. This occurrence in the "Milk River 

 region" is traceable to Dawson's Report on the Geology and Re- 

 sources in the Vicinity of the Forty-ninth Parallel, but, as in the 

 case of Plastomenus coalescens, a reading of the geological part of 

 the report shows that it came from south of Woody Mountain, 

 and 150 miles east of the Valley of Milk River, in beds of "Lignite 

 Tertiary" age. 



This species was reported by Cope from supposed Arapahoc 

 deposits east of Denver, Colorado, and is said to be "very common 

 in the Lance Creek beds," of Converse County, Wyoming. It 

 was also found by Brown in the Lance formation ("Hell Creek 

 beds") on Hell Creek, Montana, and an allied but undescribed 

 species is reported by Doctor Hay from the Fort Union. 



From this brief exposition it is clear that Compsemys victa must 

 be excluded from the Judith River fauna, and the only horizons in 

 which it is authenticated are Arapahoe and Lance formations. In 

 the treatment of this species in his Fossil Turtles of North America 

 (p. 234), Doctor Hay opines that there is so much difference in age 

 between Judith River, Arapahoe and Denver, and Lance formations 

 that it is "not improbable" that three species are represented in- 

 stead of one. Again would the responsibility be shifted from paleon- 

 tology to stratigraphy! 



3. Aspideretes foveatus (Leidy) Hay. 



The status of this species has been already considered under its 

 synonym, Trionyx foveatus, ante, p. 52. 



4. Aspideretes beecheri Hay. 



Type locality: East side of Lance Creek, Converse County, 

 Wyoming, in beds belonging to the Lance formation. Two cara- 



28 Fossil Turtles of North America, p. 234. 



