﻿Vol. 64.] SOLUTION-VALLEYS IN THE GLYME AEBA. 335 



18. Solution- Valleys in the Glyme Area (Oxfoedshiee). Bj the 

 Rev. E. C. Spicee, M.A., P.G.S. (Eead May 6tli, 1908.) 



[Plates XXXVIII & XXXIX.] 



In the plateau composed of Great Oonte rocks between the 

 Even! ode and the Cherwell there is a series of remarkable valleys 

 of similar character running in various directions. The area to be 

 briefly considered is triangular : the base is formed by the strike- 

 valley of the Up]3er Swere running north-eastwards, and by its 

 continuation from the Great EoUright water-parting running 

 south-westwards. The Dorn and the Glyme define an inner triangle 

 in this area (see map, p. 336). 



It will be seen that the streams run in many different directions. 

 Reference to a contoured map will show that there are innumerable 

 valleys connected with and opening into the numerous streams 

 draining the area, and that their trend varies. In the main, 

 however, they are either strike-valleys or dip-valleys, though in the 

 field their trend is not so evident. The valleys always begin 

 suddenly upon the plateau, and descend with steep sides along 

 winding courses into the nearest evident stream. The upper part 

 of each valley is always dry. The cross-valleys are usually dry 

 throughout. There are no terraces in the valleys, and there is no 

 drift upon the plateau, nor any alluvium in the streams. The 

 general appearance of the plateau-valleys is not of erosion but 

 subsidence, as if an enormous snake had left a cast upon a yielding 

 surface. 



Taking any part of the area, such as that where Grimm's Brook 

 enters the Glyme west of Wootton on the right bank (PI. XXXVIII, 

 fig. 2), it will be seen that the plateau consists of ordinary weathered 

 limestone-rock, and that the brook-valley enters the river-valley at 

 right angles, making no impression v^hatever upon the opposite 

 bank, but sinking into the stream surrounded by a broad marsh. 

 Higher up the brook-valley are many cross-valleys which enter the 

 brook-valley from each side, and these cross-valleys have other 

 valleys entering them also in a similar manner. The mouth of a 

 cross-valley entering the brook-valley is seen in PL XXXVIII, 

 fig. 3. A well- used farm-road runs down this valley, which simply 

 merges into the left bank of the brook-valley shown in fig. 2 with- 

 out making any further impression upon it. All the valleys above 

 the brook-valley are usually dry, but the general contour of the dry 

 valleys and the brook-valley is similar. There are no terraces. 

 The ground sinks from the plateau in symmetrical and equal 

 slopes. There is no more evidence of mechanical disturbance at 

 the mouth of any valley than there is at the source. The entering 

 valley has no effect whatever upon the course of the main valley 

 into which it simply sinks. 



Q.J.G.S. No. 255. z 



