In Silurian and Devonian Epochs 125 



Dendrodus, Glyptoponms, and Glyptolepis the formation 

 can be widely recognized over the entire "Arctic-Atlantic" 

 area. The numerous species described by Traquair (Lank- 

 Traq. in Palaeon. Soc. 1868-19 14) indicate a still greater 

 wealth for the future. The suggestive couple of papers 

 by Barrell (79:345,387) emphasize somewhat strongly a 

 fluviatile rather than a lacustrine origin for many of the 

 Old Red beds. And unquestionably if one considers flood- 

 plain possibilities, the areas of fluviatile deposition may 

 have been extensive. A combination, however, of fluvia- 

 tile, of lacustrine, and of fluvio-lacustrine flood-plain sed- 

 imentation seems better to explain the requirements of the 

 case. The valuable observations also of Rogers {81:100) 

 for North Devon, and of J. W. Evans (^2:547) for 

 North and South Devon, as for South Wales and Southall, 

 suggest that the area once covered in Britain by Upper 

 Old Red deposits may have been considerable. 



Fig. 12. Phaneropleuron andersoni, a primitive dipnoan fish 

 from Upper Old Red rocks of Scotland, about one-third natural 

 size. (From Traquair-) 



As to the wide range of the fishes, A. S. Woodward 

 writes thus (Proc. Geol. Assoc. 18 (1904) 433) : "It may 

 be said that Holoptychius and Sauripterus (or Crossop- 

 terygian genera of equal rank) with Bothriolepis and 

 Asterolepis characterize the Upper Old Red Sandstone 

 or Upper Devonian wherever it occurs — in Britain, Belgium, 

 Germany, Russia, Spitzbergen, Greenland, Canada and the 

 Catskills of New York. All assertions to the contrary 

 are based on a wrong interpretation of the fragments, 

 by which alone the fishes are so frequently represented." 



Turning now to the Devonian, Erian, or Old Red sys- 

 tem of North America we seem here to encounter a fairly 

 even continuity, but likewise alternation, in the Devonian 



