58 KNOWLTON 



but a careful reading of Dawson's account 19 of the geology of the 

 place where he actually obtained the specimens shows that in all 

 reasonable probability it should be referred to the "Ceratops beds," 

 that is the Lance formation. Dawson considered the beds as "be- 

 longing probably to the base of the Lignite Tertiary," and compares 

 them to the beds south of Woody Mountain, adding: "The bones, 

 in the manner of their preservation, much resemble division /3 of 

 the Bad Lands south of Woody Mountain, which these beds may 

 possibly represent." The lithology is described as similar in the 

 two areas, and associated with the remains of the turtles Dawson 

 reports finding many bones of dinosaurs, and large Unio shells. 

 In any event it seems unsafe to refer these beds to the Judith River 

 merely on geographical position and without corroborative data. 



The type specimens of Basilemys ogmius are said to be very poor, 

 and Doctor Hay states that : " It is doubtful whether new materials 

 could be identified by means of the type." However this may be, 

 this species has been combined with Basilemys variolosa (Cope), 

 which has as its type locality "Bad Lands of the Judith, Montana," 

 and was described a year or more later. Material that has been 

 identified as Basilemys (or Adocus) variolosa has been mentioned by 

 Lambe from the Belly River beds of Red Deer River, Alberta, and by 

 Hatcher in the Judith River formation of Montana. It seems not 

 improbable that there may be two species represented, but in any 

 event it would appear that the undoubted Judith River material 

 has been that identified with "B. variolosa," whereas the B. ogmius, 

 being very poor, has not been certainly recognized. 



The conclusion reached is that that part of the "species" named 

 "B. ogmius" came from beds that are not certainly of Judith River 

 age, and has not been subsequently recognized, while the part 

 known as "B. variolosa" came from beds of Judith River age, and 

 is the only part of the "species" that has been distinguished by later 

 authors. 



9. Basilemys imbricarius (Cope). 



Type locality: Judith River Basin, Montana, in beds of the 

 Judith River formation; it has not been found elsewhere. It was 

 founded on very unsatisfactory materials, according to Doctor Hay. 



19 Brit. N. A. Boundary Com., 1875, p. 130 et seq. 



