In Silurian and Devonian Epochs 131 



A somewhat related fish-fauna Is that from Scaumenac 

 Bay and other parts of Canada, but so far as it is now 

 known, it did not include such gigantic forms as Dinichthys 

 and Titanichthys. Eastman's condensed list {Sg-. 16, 17) 

 is as varied as it is suggestive. 



In North America, as in Europe, the fossilized fish- 

 fauna of the Upper Devonian is nearly always associated 

 with beds that are rich in eurypterids, in phyllopods, in 

 highly evolved scorpions and myriapods, In a characteristic 

 mollusc, and in finely preserved specimens of ferns and 

 lepidodendrold plants. These have been described or re- 

 ferred to by Dawson, Newberry, Claypole (op. cit. p. 342), 

 Patten {10: 2,11) and others. More than passing mention 

 however should be made of "a freshwater mollusc." 

 Originally named Anodon jiikesii by Edward Forbes, its 

 history and biological environment have been ably traced 

 by R. B. Newton (90:245) who named it Archanodon 

 jukesii. He points out that Forbes found with it, at Knock- 

 topher in Ireland, remains of the eurypterid Pterygotus, 

 of the fish Holoptychius^ also the Upper Old Red plants 

 Cyclopteris, Archaeopteris (or Palaeoptens) hihernicus, 

 Lepidodendron, and Stiginaria. Subsequently commented 

 on by Baily, Jukes, Hull, and Boyd Dawklns, it was by the 

 last compared with Cypricardites catskUlensis a* closely 

 allied form from Chenango County, New York State. In 

 Ireland as in America similar envlronal conditions evidently 

 prevailed, for he writes: "In Ireland the mollusc occurs 

 with Palaeopteris hibernica etc., Coccosteus etc., and 

 Eurypterus scouleri? etc; in Northumberland with Uloden- 

 dron ornatissimiivi and Calamites ; and in America A. cats- 

 kUlensis, the close ally of the British species, is found in 

 company with plant and fish remains {Holonema riigo- 

 stim) ." Here then we have a glimpse of a freshwater 

 biological grouping that must have been more or less con- 

 tinuous from England to America. 



So he concludes: "All these facts demonstrate that the 

 genus Archanodon was of lacustrine or fluviatile origin, 

 and that the deposition of the beds containing It, whether 

 in England, Ireland or America must have been regulated 



