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



nian, it is difficult to understand how members of the Chemung- 

 Catskill fauna could have reached Colorado, unless they came 

 by some southern route as yet unknown. On the other hand, 

 a Eurasiatic origin by way of Behring Straits cannot be 

 regarded as an impossibility, nor even as an improbability, 

 since the invertebrate fauna of the superjacent formation has 

 been shown by Dr. Girty* to be " not closely similar to the 

 faunas of the eastern and central United States," but exhibits, 

 in his opinion, " a closer parallel with the Devonian of the 

 Ural Mountains." 



Attention should also be called to Professor Calvin's obser- 

 vations on the Devonian system of Iowa, which go to show 

 that the eastern and western areas were geologically isolated. 

 According to this author, f " the eastern Devonian faunas prob- 

 ably migrated from the northeast along the eastern border of 

 the continental nucleus, while the western faunas of the same 

 period seem to have come from the northwest along the 

 western border of the Devonian continent." He also points 

 out that the Iowa Devonian fauna is related in some respects 

 to that occurring at the Ramparts of the Mackenzie River, and 

 the present writer has commented on certain resemblances 

 between its vertebrate constituents and the corresponding 

 fauna of Russia. 



For the present, the question as to the origin of the 

 vertebrate fauna of the Colorado Devonian must be considered 

 as problematical, and one which will require considerable 

 further evidence and investigation before it can be answered 

 satisfactorily. It is evident that the remains thus far obtained 

 by Dr. Cross constitute not only an important paleontological 

 discovery, but open up problems of distribution, and others of 

 a geological nature, which are worthy of careful study. 

 Harvard University, Cambridge, Mass. 



EXPLANATIONS OF FIGUEES. 



Figure 1. — Bothriolepis coloradensis sp. nov. Elbert formation; Bock- 

 wood, Col. Ventral armour, ^ natural size, avl, Antero-ventro-lateral ; 

 mo, Median ventral; pvl, Postero-ventro-laterol plates. (U. S. Nat. Mus.) 



Figure 2. — Bothriolepis major ( Ag.). Upper Old Eed Sandstone ; Elgin, 

 Scotland. Ventral armour, seen from the visceral aspect, x f . (Original 

 in Mus. Comp. Zool. at Cambridge.) 



Figure 3. — Bothriolepis major (Ag.). Median ventral, x{. Ibid. 



Figure 4. — Bothriolepis coloradensis (?) sp. nov. Fragmentary pectoral 

 appendage, x \. Elbert formation ; Devon Point, Colorado. 



Figure 5. — Holopfychius giganteus Ag. x \. Same locality. 



Figure 6. — Holoptychius tuberculatus Newb. x ^. Same locality. 



* The Carboniferous Formations and Faunas of Colorado (Profess. Paper 

 U. S. Geol. Surv., No. 16, p. 162), 1903. 



f Ann. Rept. Iowa Geol. Surv., vol. VIII (1897), p. 221. One may com- 

 pare also the following important papers on Devonian paleontology : 

 Schuchert, C, On the Faunal Provinces of the Middle Devonic of America, 

 etc. (Amer. Geol., vol. xxxii, pp. 137-162), 1903. "Williams, H. S., The 

 Correlation of Geological Faunas (Bull. U. S. Geol. Surv., No. 210), 1903. 



