TIIK .iniASSlC SVSTKM 1"''.' 



through Russia and northward t<> tin- Antic Ocean, the islands 

 in tin- westi-rn part of tln> sea are not only retained, but an- 

 so-mvly diminished in size; moreover, in hi.- " Ski-tr.h of Uxlbrdian 

 Europe" they have actually grown larger. 



British geologists believe that the subsidence of the Callovian 

 or beginning of Oxfordian time was a general one, affecting the 

 wt-.-tt-rn as much as the eastern parts of Europe. It is probable 

 that the Upper Jurassic Clays spread over the whole platform of 

 Pakeozoic rocks which underlies the east of England, and that 

 tin -.-> clays were subsequently removed partly by subaerial erosion 

 and partly by the planation of the area as it sank beneath the 

 Cretaceous Sea. My view is that the whole of the Anglo- 

 island was Miluuerged beneath the seas of Oxfordian, 

 Corallian, and Kimeridgian times, and did not reappear until the 

 Portlandian, for the thinning of the Corallian and Kinieridge Beds 

 in tin- Houlonnais is doubtless due to their subsequent planation 

 and not to their originally thinning out against a shore-line. 



Another question arises with regard to the northern extensions 

 of the Oxfordian and Corallian Seas, for some have supposed that 

 the connection between Scotland and Scandinavia was severed at 

 this time and that the Scandinavian region, together with Lapland 

 and Finland, became a large island. There can be no doubt that 

 the Middle Jurassic Sea did pass round the eastern and northern 

 sides of this land, for not only are there deposits of this age in 

 Northern Russia in the province of Volodka, but also to the north- 

 east of the White Sea and in the valley of the Petchora. They also 

 occur in Konig Karl Land and Spitzbergen, forming a succession 

 from Callovian to Kimeridgian, and beds of Oxfordian age have 

 Ix-i'ii found on the east coast of Greenland (Kuhn Island and 

 .1 ami-son Land). 



Hence it is quite possible that the Boreal Sea of Oxfordian 

 time did extend southward to Scotland and thus encircled the 

 Scandinavian region, but it is much more probable that the 

 connection with the Germano-British Sea was round the western 

 side of Scotland and across the north of England than directly 

 between Scotland and Norway. The Jurassic strata of tin- \Vc>trrn 

 Isles were undoubtedly formed in a sea which covered the north- 

 western arm of the great Triassic lake, and there is no reason to 

 suppose that Jurassic deposits were ever formed in the east of 

 Scotland south of Elgin or in the south-west of Norway. The 

 Kimeridgian Beds of Sutherland seem to have been formed in the 

 estuary of a river which may have opened either northwards into 

 the Boreal Sea or south-westward down the valley of the Great 

 CJlen. 1 see no reason for supposing that the Central Highlands 



