264 WORK AT OXFORD. [l875. 



I do not think the cause adequate to the effect. For this, and 

 the reasons I have given elsewhere, I am inclined to consider the 

 angular drift of the West and South of England all referable to 

 the cause I named in my Portland paper, viz., the submergence 

 of the land, and its emergence in a comparatively short period of 

 time like that which might, for example, accompany a series of 

 earthquake movements. This would give a considerable trans- 

 porting power, but a transport neither of sufficient distance nor 

 of sufficient duration to produce much, or any, wear of the 

 materials which we might expect to find in and under this 

 (landwash), namely, the remains of the land animals and land 

 shells which lived on the submerged land. I take the red mud 

 deposit with its heaped collection of bones to be evidence of the 

 slowly advancing waters, and of the animals drowned in the 

 plains; while the angular debris is evidence of the more rapid 

 emergence and off-flow of the waters, carrying down the slopes 

 of the hills, and for some distance into the plains and valleys, the 

 loose debris of the submerged hills. 



This hypothesis seems to me to explain the greater number 

 of phenomena, and to keep a reasonably harmonious relation 

 between the several sets of them. It is one I have not arrived 

 at hastily. It has, in fact, been the result of many years' observa- 

 tions. Still I am not at all wedded to it, and if it can be shown 

 that ice and snow or any other causes are more likely to have 

 been the agents which have operated that remarkable series of 

 changes of which you have so interesting an example in the 

 Severn Valley, I shall be most happy to adopt a theory which 

 seems better or truer. 



I now have to thank you for two very pleasant days which I 

 enjoyed much, though to my regret I found out that my walking 

 powers are not what they were ; and with the kind regards of Mrs 

 Prestwich and myself to Mrs Symonds, believe me to be very 

 truly yours, J. PRESTWICH. 



During the first few years at Oxford, Prestwich's 

 time was absorbed by the preparation of his lectures 

 and by work connected with the collections at the 

 Museum ; and, having no scientific assistant, he found 





