464 PLEISTOCENE DEPOSITS. CHAP. 



Ampney deposit, traversed in narrow channels by the existing 

 streams, suggests the idea of deposition from land floods in a sheet 

 of water subject to agitation. This gravel is about 270 feet above 

 mean tide. 



Where the Windrush directs its course toward the main stream 

 a great body of gravel spreads on both sides, sloping gently south- 

 wards as the river descends. At Witney and Eynsham it is largely 

 dug, from 260 to 200 feet above the sea, in thin undulated layers 

 of oolitic stones, sand, and flints, with a considerable proportion 

 of red quartzite. At Stanton-Harcourt it is partly consolidated to a 

 conglomerate by infiltrated carbonate of lime and carbonate of iron, 

 so as to be actually employed in building. At Yarnton the deposit 

 is very extensive, and as much as 12 and 16 feet deep. It is 

 formed of many irregular, mostly undulated layers of gravel and 

 sand, with thin stripes of clay; the stones mostly oolitic, with 

 admixture of flints, red grits, and white quartz ; the height above 

 the sea is about 210 feet. It yielded at and near the bottom, 

 where large pebbles of northern drift formed an almost solid bed, 

 a profusion of teeth and tusks of Elephas primigenius. In the 

 upper part were old British pit-graves, with skeletons in the pits. 



This gravel spreads northward up the sides of the curious hollow, 

 which may have been an old channel of the Cherwell, to Kidlington 

 Station, where it is in laminae of stones, sand, and thin clay bands, 

 yielding a few shells of land and fresh-water. 



Oxford stands on a gravel bed, 8, 12, or even 16 feet thick, 

 between the Thames and the Cherwell, and is supplied with water 

 of good drinking quality by the rain which is filtered through 

 the gravel and collected on the clay. On the left banks of 

 the Cherwell a little, and in Cowley Field much gravel ; on the 

 right bank of the Thames, at Wytham, and North Hinksey, and 

 indeed under a good part of the valley, gravel occurs. The height 

 of this gravel-bed at Oxford above the mean level of the sea is 

 about 210 feet. 



Abundance of Gryphsea dilatata, Belemnites sulcatus, and Isastrsea 

 explanata, from Oxford clay and Coralline oolite, with fossiliferous 

 fragments of Forest marble, occur in all situations. Flints almost 

 unmixed with other materials occurred in an excavation at Summer- 

 town, but we sought there in vain for any ancient implement. 

 Bones of the mammoth, rhinoceros, hippopotamus, ox, deer, and 



