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obtain, and that the subject is very complicated and difficult to 

 unravel. This is not sui'prising, considering the great changes 

 which have taken place in the surrounding country since the 

 Cotteswolds first became dry land. It is, however, a subject 

 well worthy our consideration ; and in elucidating the truth, we 

 add an interesting chapter to the records of geological science, y^^^ 



I need not, of course, offer to Cotteswold Naturalists any 

 description of the physical character of the district, farther 

 than is necessary to illustrate the line of argument which I 

 propose to take in connection with the subject of denudation. 

 I may, however, refer to the geological map, and briefly to note 

 some few particulars. (1.) It is seen that the south-eastern 

 slopes of the upper Cotteswolds are drained into the Thames, 

 those of the lower Cotteswolds into the Avon, while on the 

 north-western side the whole drainage is into the Severn. 

 (2.) The number of streams which are raised to the dignity of 

 rivers, considering the extent of the district, is large ; still more 

 strikiiig is the multitude of streamlets which make up the 

 volume of the rivers. The principal streams are the Evenlode, 

 Windrush, Leach, Coin, Churn, and Swill-brook, all tributaries to 

 the Thames ; the lower Avon, whichhas its separate drainage area, 

 and the Chelt, Isborne, Frome, and Cam, with several brooks of 

 considerable volume, which fall into the Severn. (3.) The sources 

 of the rivers are generally near the centre of the range, and 

 though the head-spring is frequently insignificant, the surface 

 drainage of the Lias, the Fullers Earth, the Forest Marble, and 

 Oxford Clay, is considerable, and large quantities of storm 

 waters are thus carried off into the Thames, Severn, and Avon. 

 (4) The sources of the rivers are either in the Lias or Fullers 

 Earth, but as respects those which flow westwards, their valleys 

 have been excavated through the escarpment of the Cotteswolds, 

 although the escarpment must once have been at a greater 

 altitude than the strata on which the rivers have their source. 



From these conditions it is only reasonable to suppose that 

 the country would be very much intersected by deep valleys, 

 the character and extent of which would be influenced by the 

 volume of the rivers, their velocity, and the nature of the strata ^ 

 through which their channels were excavated. ^^ 



