258 C. R. Eastman — Upper Devonian Fish Remains. 



Agassiz, allowance having been made by him for variation 

 amongst scales belonging to different parts of 4 the body in the 

 same fish. The species was subsequently divided by Newberry, 

 who included under the name of H. tuhefculatus those scales 

 in which the tubercles remained distinct, and were not fused 

 into continuous, longitudinal ridges. As for Newberry's H. 

 americanus, this resembles Agassiz's species in having the 

 ridges irregularly tortuous, and more or less interrupted and 

 branching, hence it will be seen that the precise determination 



Fig. 5. 



— Holoptychius giganteus 

 Ag. Scale, x \. 



Fig. 6. — Holoptychius tuber culatus 

 Nevvb. 



of detached scales is a matter of some difficulty. Probably 

 we shall not err greatly in identifying the original of fig. 5 as 

 H. giganteus Ag., and that of fig. 6 as H. tuberculatus Newb. 



Engineer Mowitain Quadrangle. 

 From Station No. 209, a locality on Little Cascade Creek, 

 one half mile south of Columbine Lake, Engineer Mountain 

 Quadrangle, a single finely tuberculated plate was obtained by 

 Dr. Cross, which appears to be a posterior ventral of some 

 Arthrodire, of about twice the size of the type species of Coc- 

 costeus. Occurring as it does in the detached condition, and 

 more or less injured by weathering, even an approximate deter- 

 mination is impossible. 



Pitkin County. 

 The few fragments obtained by Mr. Spurr from the vicinity 

 of Aspen are poorly preserved, and specifically indetermin- 

 able."* Two or three finally tuberculated plates are probably 

 to be regarded as of Arthrodire nature, and the presence of 



* This remark applies only to the small portion of Mr. Spurr's collection 

 which has as yet come under the writer's observation. At the time this 

 article was written, it was not practicable to obtain access to the remaining 



