Physical Geography. 257 



of this vast Eocene continent. Of this, however, we 

 may be sure, that somewhat altered in form and somewhat 

 lowered by waste, the old Silurian lands of Wales, the 

 north of England, and the Scottish mountains formed 

 part of the Continent that gave birth to the Eocene 

 river. The Eocene formations of the London basin 

 all thin away as we pass from east to west, and it 

 seems as if originally there had been a landward edge 

 to the estuary in that direction, and possibly, but quite 

 uncertainly, the river may have flowed through wide 

 lands that stretched far to the west and north-west, or, on 

 the other hand, it may have flowed through broad tracts 

 of what is now part of the Continent of Europe. However 

 that may be, I have no doubt that tributary streams 

 poured into it from the west and north-west, for to my 

 mind it is certain, that beyond the original edge of 

 these Eocene formations, the Chalk spread far to the 

 west, till it abutted on and probably rose high on the 

 sides of the mountains of Wales, and passing westward 

 on the south through the area of the present Bristol 

 Channel, and on the north, across the space now occupied 

 by the estuaries of the Dee and the Mersey, the Chalk 

 of England formed a broad undulating plain, united to 

 the Chalk of Antrim and the Cretaceous rocks of what 

 is now the Western Isles of Scotland, which then formed 

 part of the mainland, long before those volcanic erup- 

 tions took place that overspread the Chalk of Antrim 

 with sheets of basalt, and gave rise to the present 

 mountain scenery of the Inner Hebrides. If so, these 

 upraised Cretaceous strata must have spread westward 

 into areas now covered by the Atlantic, but of its actual 

 extent nothing is certainly known. 



Such is a general sketch of what I believe to have 

 been the state of the Physical Geography of Britain 



s 



