C. B. Eastman — Upper Devonian Fish Remains. 259 



Dipnoans is indicated by certain smooth scales displaying their 

 characteristic perforations. These latter, however, are note- 

 worthy for furnishing the only indication we possess at present 

 of the occurrence of Lung-fishes in the Colorado Devonian. 



General Conclusions. 



It has already been remarked that the remains brought to 

 light by Dr. Cross are indicative of an Upper Devonian hori- 

 zon. No other conclusion seems possible in view of the fact 

 that Bothriolepis is an exclusively Upper Devonian genus, and 

 the greater number of Holoptychius species occur in beds of 

 the same age. The two species of the former genus already 

 known from this country, and dozen or so of Holoptychius, 

 are limited to the Chemung and Catskill groups of New York 

 and Pennsylvania. One species of Bothriolepis (B. canadensis 

 Whiteaves), and one of Holoptychius, have been described 

 from the Upper Devonian of the Province of Quebec, Canada. 

 These genera are represented abroad by various species found 

 in the Upper Old Red Sandstone of Scotland, and in the 

 Upper Devonian of Belgium and Northwest Russia. The 

 vertebrate fauna of which they form part is composed of 

 Ostracophores, Arthrodires, Dipnoans, Crossopterygians and 

 Elasmobranchs, and it is interesting to note that all of these 

 groups with the exception of the last-named are represented in 

 the Colorado Devonian. 



Regarding the origin of the Colorado fauna, little can be 

 said with positiveness. The new species of Bothriolepis appears 

 to be most closely related to B. major of Scotland and Russia, 

 and if the fragments showing vermiculated ornamentation are 

 correctly interpreted as belonging to B. leidyi, this identifica- 

 tion, with that of Holoptychius giganteus, place the fauna in 

 relation with the Catskill of Pennsylvania. The Chemung- 

 Catskill of the eastern States betrays an unmistakably Euro- 

 pean origin, but there is good reason to suppose that a barrier 

 existed between the eastern and western regions during the 

 late Devonian, since neither Holoptychius nor Bothriolepis 

 remains have been found west of New York and Pennsylvania. 

 From this latter region also, the Upper Devonian Ptyctodonts 

 and Dipnoans of Iowa and contiguous States were entirely 

 excluded. Assuming that there was no connection between 

 the eastern and western areas toward the close of the Devo- 



specimens, nor to the interesting material collected by Dr. C. D. Walcott 

 from the lower Kanab canyon of Arizona in 1879, owing to the limited 

 storage facilities of the Museum, and absence from Washington of the proper 

 custodians. Mr. Walcott's only publication in regard to the Kanab material 

 is to be found in this Journal [3], vol. xx, p. 224. 



The Aspen material is briefly described by Dr. G. H. Girty, in vol. xxxi, 

 p. 20, of XT. S. G. S. Monographs (J. E. Spurr: Geology of the Aspen Mining 

 District). Without having actually seen the teeth, which are there provision- 

 ally referred to "Ehizodus," a Carboniferous genus, we may be permitted 

 to hazard the presumption of their belonging to Holoptychius. 



