DEVONIAN AND OLD RED SANDSTONE SYSTEM 239 



Bothrodendron kiltorkense, and four other species with Stigmaria 

 faoides and others. There are also remains of the fish Holoptychius 

 giganteus and H. monilifer. 



Again Upper Old Red has been found on the east coast of 

 Greenland, the beds being red and brown sandstones from which 

 fish of the genera Holoptychius and Asterolepis have been obtained. 



From these facts it is clear that the Old Red Sandstone facies 

 has a very large extension in the Arctic regions, and that the 

 continent within which these deposits were formed reached from 

 England to Spitzbergen, and from Greenland at least as far as 

 Sweden, and probably through Northern Russia where sands and 

 mark with fish remains occur near Archangel, without any marine 

 deposits, but marine Devonian strata do occur in Novaya Zembla. 



C. GEOGRAPHY AND HISTORY OF THE PERIOD 



The general geographic conditions under which both the 

 marine Devonian and the Old Red Sandstones were deposited 

 have been fairly well indicated in the preceding pages, and the 

 student will doubtless have realised that the greater part of Northern 

 Europe, together with the whole of the North Sea area and part 

 of the Atlantic Region, formed at this period a large continental 

 tract of land. By some authors the Devonian has been called 

 " the first continental period," regarding it from a European point 

 of view, and it is certainly the earliest period for which we can 

 reconstruct a map of land and sea with anything like an approach 

 to accuracy. 



I have therefore prepared a map of Northern Europe in Lower 

 Devonian time (Fig. 80) and will briefly recapitulate the data on 

 which the southern boundary or coast-line of the continent has 

 been drawn. Beginning with the western region the great thick- 

 ness of detrital ieposits and the prevalence of fine sand in Brittany, 

 Cornwall, and the south-westof Ireland are plain indications that they 

 must all have been on the borders of a large area of land. We find 

 actual portions of this land in Waterford, Wexford, and South 

 Wales, and again in the southern part of Cornwall. Hence we 

 arrive at the conclusion that the area in which the Glengarriff 

 Beds were deposited was a large land-locked bay bounded by 

 continental land on the north, west, and south, and only opening 

 eastward through a channel from 50 to 70 miles in width. 



From Cornwall the land seems to have projected as a pro- 

 montory into the area now occupied by the English Channel, and 

 its southern shore must have passed outside Brittany and then 

 south-westward toward the north of Spain. In Asturia the lowest 



