GEOLOGY 



sculptured prior to the Glacial epoch, yet during that epoch and in 

 subsequent times considerable modifications were brought about by the 

 accumulation of material as well as by erosion. 



The valley gravels which border the present rivers lie in hollows 

 cut through the plateau Drifts. They are evidently newer, but whether 

 they are wholly Post Glacial is difficult to decide, as in both North and 

 South Wales there is evidence that Glacial action continued later than 

 some of the deposits which contain mammalia, like those found in the 

 older Thames valley deposits. 



If following Ramsay 1 we believe that the Thames drainage com- 

 menced when the Chalk and Eocene strata extended much further to 

 the west and north-west, and flowed across a gently inclined plane 

 towards the south-east, its general course was marked out perhaps in 

 Miocene times ; but there are no deposits along its valley which date 

 back beyond the Pleistocene period. Subsequent physical changes may 

 have removed such deposits, while the wasting away of the Chalk 

 escarpment must have modified the extent and direction of the drain- 

 age. The Bedfordshire Ouse, according to Professor W. M. Davis, 2 

 was a subsequent stream which beheaded certain northern streams 

 originally connected with the Thames drainage. Among these is the 

 Tove, which now joins the Ouse near Stony Stratford ; while the 

 Ouzel may have been formed later on as an obsequent stream, as it 

 flows northwards into the Ouse at Newport Pagnell. The Thame is 

 regarded as a subsequent stream, and likewise the Colne which cuts off 

 the waters of the Misbourn and Chess. 



If however we judge by the mammalian and other remains found 

 in the gravels of these valleys, it is difficult to make any distinction in 

 point of age. They all belong to the Pleistocene period. Thus in the 

 Thame valley, not far from the borders of Buckinghamshire, between 

 Shabbington and Rycote, remains of elephant have been found. 3 



At Taplow remains of the musk ox have been discovered, 4 and in 

 the lower parts of the Thames valley the gravels and brickearths have 

 yielded many mammalian remains and palaeolithic implements. Again 

 in the Ouse valley of Bedfordshire there have been found numerous 

 palaeolithic implements ; and in the Ouzel tributary remains of elephant 

 (mammoth) have been recorded from Linslade. 



The Alluvium, which is the tract of level ground bordering the 

 streams and liable to be flooded when they overflow their banks, 

 occupies but small areas in the county. Wider tracts are seen along 

 the Colne valley than along the Thames or the Ouse. These are 

 mostly meadow land, and should always be avoided as sites for human 

 habitations. Even the low-lying valley gravels bordering the Thames 

 are liable in places to be inundated, and elsewhere they may prove 

 damp as sites for dwellings, hence all living rooms should be well 



1 Quart. Journ. Geol. Soc. xxviii. 152 ; see also A. Strahan, Proc. Geol. Assoc. xiv. 405. 



8 Geograpb. Journ. v. 127 (1895). 3 T. Codrington, Quart. Joum. Geol. Soc. xx. 374. 



4 Owen and Prestwich, Quart. Journ. Geol. Soc. xii. 124, 133. 



