In Silurian and Devonian Epochs 117 



there was, on the contrary, continuous depression, and the 

 sea overspread this area, in which were deposited the Lower 

 and Middle Devonian beds. With the Upper Devonian 

 stages or Old Red Sandstone proper, the submersion of the 

 western and northern portions of the British Isles began. 

 Lacustrine conditions were established in the south of 

 Ireland, portions of Scotland, and the north of Ireland. In 

 the waters of these lakes the Old Red conglomerates and 

 succeeding beds with Anodonta were laid down." 



Speaking of the Ludlow area (5<5:434) A. S. Wood- 

 ward says : "The red sandstones, marls, and included nod- 

 ular limestones (locally known as cornstones) ^ which are 

 definitely determined at many points to constitute the lower 

 part of the Old Red series formed in the "Welsh Lake," 

 contain numerous fish-remains of the genera Pteraspis, 

 Cephalaspis, and Phlyctaenaspis. This is the typical Lower 

 Devonian Fish-Fauna, and occurs with slight variations 

 in regions as remote from each other as Cornwall, South- 

 ern Scotland (especially Forfarshire), Galicia, Spitzbergen, 

 New Brunswick and Newfoundland. The rocks containing 

 tlie fish remains, indeed, are almost identical in the Welsh 

 area, Spitzbergen, and Newfoundland; and if specimens 

 from these different localities were mixed it would be 

 difficult to separate them correctly. . . . Fragments of 

 Styloniirus and other Eurypterids are occasionally discov- 

 ered with the fish remains." 



In contrast to the above observers Macnair and Reid 

 {74'- 106) have attempted a destructive criticism, and have 

 advocated a marine origin for the Old Red Sandstone beds, 

 but they entirely fail to show why a typical marine inver- 

 tebrate fauna is not associated with the enclosed organisms; 

 they fail to note the great abundance of Estheria mem- 

 branacea, which like the entire group of Phyllopoda — past 

 and present — have only freshwater associations; they do 

 not note that the plants found side by side with the euryp- 

 terids, fishes, and Estheria, are absent from the marine 

 strata. Other grave objections can be taken to their con- 

 clusions, even on lithological grounds. It should be said, 

 however, that occasional inroads of the sea, specially in 



