56 KNOWLTON 



of Milk River it followed that the age must be Judith River ! Upon 

 this assumption alone rests the claim. 



This species has been found by Barnum Brown in the Lance 

 formation ("Hell Creek beds") 12 miles south of the Missouri 

 River, on Hell Creek, Montana. This locality is about 100 miles 

 directly south of the type locality in Canada. 



5. Plastomenus punctulatus Cope. 



Type locality: Bijou Creek, 40 miles east of Denver, Colorado, 

 in beds that are of Arapahoe age according to Whitman Cross. 

 Cope also states that he had the same species from beds at Long 

 Lake, "Nebraska" (now North Dakota), the age of which is Lance 

 formation. 



Hatcher's reason for including this species in the Judith River 

 fauna is interesting. He quotes 14 Cope's statement, evidently from 

 his Vertebrata of the Cretaceous Formations of the West, to the 

 effect that it was "found in association with the preceding species," 

 which, in this book happens to be Plastomenus costatus, but in the 

 place where P. punctulatus was originally described, 15 the "preced- 

 ing species" happens to be Trionyx vagans, the status of which has 

 already been considered above. As the original description was 

 transcribed without change from the Annual Report into the Mono- 

 graph the error arose as stated above and as has been pointed out 

 by Doctor Hay. Plastomenus punctulatus can, therefore, lay no 

 claim to having been found in the Judith River. 



6. Plastomenus insignis Cope. 



Type locality: Bijou Creek, 40 miles east of Denver, Colorado. 



This species was introduced into the Judith River fauna by 

 Hatcher 16 who, consulting Cope's Vertebrata only, and ignoring the 

 original place of publication, concludes that by "inference" it came 

 from south of Woody Mountain, and if from this locality it. was 

 assumed, as in the cases of the several species above considered, that 



14 U. S. Geol. Surv., Bull. 257, p. 74. 



15 U. S. Geol. and Geogr. Surv. Terr., Ann. Rept., 1873 (1874), p. 453. 



16 U. S. Geol. Surv., Bull. 257, p. 75. 



