PROCEEDINGS 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



VOL. XIII, No. 3, PP. 51-65. AUGUST 15, 1911 



REMARKS ON THE FOSSIL TURTLES ACCREDITED TO 

 THE JUDITH RIVER FORMATION. 1 



BY F. H. KNOWLTON. 



In my paper entitled The Stratigraphic Relations and Paleon- 

 tology of the ' Hell Creek beds, ' ' Ceratops beds' and their equiva- 

 lents, and their reference to the Fort Union Formation, 2 I made, 

 among others, the following statements regarding the turtles of 

 the Judith River formation: "It has recently been confidently 

 asserted on eminent authority that the turtles of the 'Ceratops 

 beds' are very closely related to those of the Judith River formation; 

 in fact that several species are identical, and others so close as to 

 be separated with difficulty. Fortunately the work of Hatcher, 

 published as late as 1905, has left us with a very complete annotated 

 list of the Judith River forms, which makes a valuable basis of com- 

 parison of the two faunas. It needs, however, but a cursory exam- 

 ination to show that at least half of the species listed as belonging 

 to the Judith River do not belong to this fauna at all, but come from 

 the Fort Union, Arapahoe, etc., or are so fragmentary as to be 

 unidentifiable. . . . Any comparison of the turtles of the Ju- 

 dith River formation with those of the 'Ceratops beds' as tending 

 to support the Cretaceous age of the latter, does not make a very 

 impressive case." 



1 Published with the permission of the Director of the United States Geological 

 Survey. 



2 Wash. Acad. Sci., Proc., vol. xi, 1909, pp. 235, 236. 



Proc. Wash. Acad. Sci., August, 1911. 



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