DEVONIAN AND OLD RED PERIOD. 151 



tain, and it contains no indubitable marine fossils. It has 

 been now shown, however, that the marine Devonian strata of 

 Devonshire and the continent of Europe contain some of the 

 most characteristic of the Old Red Sandstone fishes of Scot- 

 land ; whilst the undoubted marine deposit of the Corniferous 

 limestone of North America contains numerous shark-like and 

 Ganoid fishes, including such a characteristic Old Red genus 

 as Couosteus. There can be little doubt, therefore, but that the 

 majority of the Devonian fishes were truly marine in their habits, 

 though it is probable that many of them lived in shallow water, 

 in the immediate neighbourhood of the shore, or in estuaries. 

 The Devonian Ganoids belong to a number of groups; and 



Fig. 102. Fishes of the Devonian rocks of America, a. Diagram of the jaws and teeth 

 of Dinichthys Herizeri, viewed from the front, and greatly reduced ; 6, Diagram of the 

 skull of .\lacropetaiichthys Siillivanti, reduced in size ; c, A portion of the enair.elled sur- 

 face of the skull of the same, magnified ; d, One of the scales of Onyclwdiis sigmoides, of 

 the natural size ; e, One of the front teeth of the lower jaw of the same, of the natural size :_/", 

 Fin-spine of Mach&racantkus major, a shark-like fish, reduced in size. (After Newberry .) 



it is only possible to notice a few of the most important forms 

 here. The modern group of the Sturgeons is represented, 



