402 



J. BARRELL INFLUENCE OF CLIMATES ON VERTEBRATES 



several divisions of the British Old Eed Sandstone. The material for 

 tabulation was restricted to that of certain papers which specified the 

 horizons and localities of the fossils. Consequently the total number of 

 fossils is not quite as large as is known, but arguments from this selected 

 list may be more safely drawn. 12 



Distribution of Genera and Species — Old Red Sandstone Fishes of Scotland 





i)own 



ton i an 



Lower Old Red 



Middle Old Red 



Upper Red Oak 





Genera 



Species 



Genera 



Species 



Genera 



Species 



Genera 



Species 



Ostracodermi : 



















Heterostraci .... 



3 



7 



2 



2 







1 



1 





2 



2 















Aspidocephali . . . 



1 



1 



1 



3 











Antiarcha 











2 



10 



2 



2 



Selachii : 



















Acanthodii 



* 





5 



15 



4 



17 





t 



Arthrodira 











1 



6 



1 



1 



Dipnoi : 



















Ctenodipterini . . 











1 



3 



4 



4 



Ganoidei : 



















Crossopterygii . . 







.... 





7 



20 



3 



4 



Heterocerci 







.... 





1 



6 







* Some shark spines are found, however, below the Downtonian in the Upper Ludlow. 

 They are classified with the ichthyodorulites. 



t Two acanthodians are listed by A. S. Woodward as occurring at Scaumenac Bay, 

 Quebec. The writer has not examined this section, but most of it is doubtless conti- 

 nental in origin. 



Eastman in 1907 published a memoir which gives lists of all the known 

 Ordovician, Silurian, and Devonian fishes of North America. 13 These 

 are geologically arranged and give the localities of their occurrence. The 

 Devonian of North America was not characterized by internal basins to 

 the extent which is found in Scotland. Except in the maritime prov- 

 inces of Canada, the fresh-water beds appear to have been deposited 

 mostly on delta plains marginal to shallow seas, and the conditions for 

 the preservation of fish fossils of the fresh waters were much less favor- 

 able than in Scotland. In the Catskill deposits, for instance, the fossils 

 occur mostlv in the transitional zone, at the bottom of the tme land 



12 The lists of fossils used are found in the following references : 

 Trans. Roy. Soc. Edinburgh, vol. xxviii, pt. ii, p. 452. 

 Silurian rocks of Britain, vol. i, p. 684. 



Geology of East Fife, p. 358. 



A. Geikie : Text-book of geology, pp. 1006-1012. 



Geological Mag.. 1904, pp. 591-602. 



Geological Mag., 1912, p. 511. 



The catalogue of fossil fishes, by A. S. Woodward, British Museum of Natural His- 

 tory, is the most complete single work. It was examined and its data tabulated for the 

 subclasses of Elasmobranchii, Holocephali, and for the Ichthyodorulites, but the results 

 were not found to be essentially different from the result of the lists as here compiled. 



13 C. R. Eastman : Devonic fishes of the New York formations, Mem, 10, N. Y. State 

 Museum. 



