DEVONIAN AND <M.1> KKD SANDSTONK SVSTKM 225 



A. FLORA AND FAUNA 



The fauna of the Old Red Sandstone is not a large one, but in 

 < i-rtaia localities remains of fish and Eurypterids occur in some 

 abundance ; plants also occur, but the only Mollusc yet found is 

 the Archanodon Jukesi of the Upper Old Red, and this more closely 



Fig. 75. FOSSILS OF THE UPPER OLD RED 8AHDK I 



". Holyptychius nobilissimu*. b. Phaneropleuron Anderaoni. 



c. Archanodon Jukesi. 



resembles a fresh-water mussel than any marine form. From this 

 limited fauna, and the total absence of any unquestionably marine 

 species, it has been supposed that the Old Red Sandstones were 

 lacustrine deposits, and that the greater part of Northern Europe 

 was at this time a continent, within which lay several large lake- 

 areas comparable to those of North America at the present day. 

 The plants of the Old Red Sandstone are the ancestors of the 



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