512 ME. P. W. HARMER ON THE [Nov. I907, 



In an insular country like England, the latter would have been 

 trenched, I think, by longitudinal rivers, capturing the drainage 

 of the higher land and forcing a way out to sea, before any 

 important transverse stream flowing from one escarpment to the 

 other could have established itself. As soon as such a longitudinal 

 river had come into existence, all communication between the 

 drainage-systems of the regions on each side of it would have 



The breaching of the Chalk at the Wash, and at the gap 

 separating the Wolds of Lincolnshire from those of Yorkshire, may 

 have taken place at a more remote period ; but the group of short 

 gorge-like valleys of a Panama-Canal type discussed in this paper, 

 few in number, and as to Central England unique in character, 

 originated, I suggest, under different conditions, and at a com- 

 paratively recent date. These valleys, crossing transversely ridges 

 of high land, and cut down to the level of the plains which they 

 connect, 1 are associated with lake-like areas of depression, the 

 original drainage of which must have been obstructed by the 

 Glacial ice. 



I offer no apology for the somewhat speculative character of 

 this paper. It is not the first time that the question of valley- 

 erosion has been so treated. Whether or not the views here taken 

 be accepted, I trust that the enunciation of them may at least 

 provoke further discussion. 



I cannot conclude without expressing my indebtedness to 

 Messrs. J. Bartholomew & Co. for having kindly permitted me to 

 make use of their admirable contour-maps. The value of the latter 

 to students of geology or physiography has yet to be fully recognized. 



My thanks are also due to friends who have given me information 

 and help in various ways, among whom I may especially mention 

 Mr. E,. H. Rastall and Mr. H. J. Osborne White, who accompanied 

 me in some of my excursions, Mr. H. B. Woodward, and Prof. P. F. 

 Kendall. I desire, moreover, to acknowledge the kind way in 

 which Mr. G. W. Lamplugh and his colleagues, Messrs. Gibson, 

 Wedd, Sherlock, and Smith, placed at my disposal the information 

 obtained during their survey of the district around Melton Mowbray. 



EXPLANATION OF PLATES XXXI-XXXV. 



Plate XXXI. 



Contour-map of a portion of the Cheshire Plain and the surrounding district 

 (showing also the gorge at Ironbridge and the great accumulation of erratic 

 boulders near Wolverhampton), on the scale of 6 miles to the inch. 



1 This seems to be the special feature by which overflow-channels like those 

 at Ironbridge or Goring differ from some other sharply-cut valleys, in other 

 respects more or less resembling them. 



