122 Evolution and Distribution of Fishes 



of marine origin, and consequently that their "mailed" fishes 

 were inhabitants of the sea. This is however not strange 

 when we remember that mailed fishes {Pterichthys, etc.) 

 also occur in the Middle Devonian Limestone of the Eifel, 

 in company with such purely marine fossils as crinoids and 

 brachiopods." The writer might advance possible explan- 

 ations regarding the above undoubtedly exceptional rela- 

 tions, but would preferably desiderate a more critical study 

 of the rock-successions in connection with their contained 

 fossils. That the organisms thus grouped together, lived 

 in distinct freshwater and marine environment, seems to 

 the present author assured. 



The Upper Old Red rocks of Europe are represented 

 over a wide range of country from South-east Ireland across 

 Central Scotland to Norway, Russia, and probably even 

 Spitzbergen. So this range would include a considerable 

 part of Freeh's Arctic-Atlantic continent. The strata are 

 on the whole of a lighter color than the lower Old Red 

 rocks, though ferruginous red predominates. The richest 

 fossiliferous rocks are also here of a hard fissile argillaceous 

 or argillo-calcareous type, that might again suggest rapid 

 deposition of volcanic dust. This is eminently true of the 

 celebrated "cyclopteris" or Kiltorcan rocks of South-east 

 Ireland and of northern Scotland. From these areas large 

 and beautifully preserved leaves of Palaeopteris {Archae- 

 opteris) , stems of Knorria, Calamites, Lepidodendron and 

 other drifted land plants have been abundantly secured. 

 In Ireland the freshwater lamellibranch Anodonta jukesii 

 is associated with these. The freshwater phyllopod Es- 

 theria membranacea is still abundant, and in this con- 

 nection no palaeontologist has been a more consistent and 

 yet unconscious advocate for the freshwater habitat of 

 primitive fishes than Rupert-Jones. Thus, in recording the 

 finding of Estheria by C. W. Peach in three quarries in 

 the parish of Wick (ySiii) he observes that "Dipterus, 

 Diplopterus, Osteolepis, Glyptolepis, and Coccosteiis with 

 land plants are also found in these quarries," and he ac- 

 companies this with such statements as: "In the Estherian 

 flagstones of Caithness we have no evidence of any marine 



