Rivers of Scotland. 529 



My own opinion is, that all the valleys of the South 

 of Scotland may be said to have been formed gener- 

 ally contemporaneously with the valleys of the adjoin- 

 ing region of the north of England already described. 1 



Of this we are certain, that some very ancient 

 valleys in Scotland are older than the Old Red Sand- 

 stone, the deposition of which has more or less rilled 

 them with detritus, and they are now being re-exca- 

 vated by running water. Taken as a whole, most of 

 them may be said to be as old as the river-made valleys 

 of Wales and Cumberland, for the disturbances which 

 affected the Silurian and other palaeozoic formations of 

 Scotland were coeval with those that first raised the 

 mountains of Cumberland, Wales, and Ireland high 

 above the level of the sea. 



1 A model of the Thames Valley, by Mr. J. B. Jordan, coloured 

 geologically, may be seen at the Geological Museum, Jermyn Street. 

 It clearly explains the relation of the river to the Oolitic and 

 Cretaceous escarpments, pp. 513-15. 



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