Douglass : Vek iebrates from Montana Tertiary. 199 



The symphysis was quite long. The distance from the symphysis 

 to P] is about the same as the length of P.j. 



The mandible is that of an individual so young that I cannot at 

 present assign it to any species. 



Explanation oi- Plate. 

 Contact showing unconformity between White River and Loup Fork beds, near 

 Big Round Top about nine miles north of Logan, Lower Madison valley, Montana. 

 The lower distinctly stratified beds are White River and at adjacent localities 

 numerous fish remains were found. The upper less regularly stratified beds are Loup 

 Fork and contain fossil plants and mammals. 

 Carnegie Museum, February 25, 1903. 



