178 



The Geology of the Berks 8f Hants Extension, 



ordinary chalk, and do not suffer from the action of frost. 

 At about 4 feet below the Chalk-rock there is here a succession 

 of irregularly shaped cavities filled with a brown sand, probably of 

 Tertiary age, which has found its way beneath the Chalk- rock from 

 its outcrop on the surface, and not through it in sand pipes. The 

 Chalk-rock dips at an angle of 27" nearly true north, and higher up 

 at the road from Wootton Rivers to Forest Gate, the dip is as 

 much as 45" in the same direction. The Chalk here appears to have 

 suffered considerable tilting up and denudation before the deposi- 

 tion of the Tertiary beds ; otherwise sand of the latter age could 

 hardly have penetrated into the lower-chalk. The present surface 

 of the hill is free from any drift, only a few inches of soil 

 covering the chalk. The thickness of the Lower-chalk appears to be 

 about 360 feet, but the data are insufficient for accurate measure- 

 ment. 



Fig. 5 repre- 

 . flints gents a disturb- 

 ance in theChalk- 

 ••^'"'* with -flints, visi- 

 ble near the end of 

 the cutting, and 

 on each side of 

 it. It does not 



Fig. 5. Section near road from Wootton Rivers to Forest-gate. appear tO be a 



fault, as the lines of flint resume their course after passing through 

 it. The sides are marked by sharp lines, within which the chalk 

 looses its regular stratification and becomes confused. A band of 

 flints dips down in a V shape, in which the flints are not so continuous 

 as in the undisturbed portions. Above the V the chalk is inter- 

 mingled with brown clay, and lies in curves. 



Inoceramus Brogniartii, Spondyhis sjnnoHus, Terehratula carnea, 

 Micraster cor-anguinum occurred in the Upper-chalk here. 



On reaching the high table land, we come to a succession of cut- 

 tings very similar in character. 



A drift of re-arranged Tertiary beds lies on the chalk, the upper 

 surface of which is exceedingly irregular. This drift is principally 



