BAGSHOT STRATA FROM ALDERSHOT TO TVOKINGHAM. 503 



of about 500 feet. In the wells mentioned on the southern slope of 

 Hungrj' Hill nothing but buff-yellow sand, occasionally more 

 deeply stained with oxide of iron, was met with, and the water- 

 bearing stratum was described to me as a " stiff yellow loam." 



Prom the facts just mentioned it would appear that beds high up 

 in the Bagshot Series rest against the London Clay in these hills. 



7. Valley north of Wellington College Station (comp. fig. 2). — - 

 Turning to the geological map, we find the northern boundary of the 

 Middle Bagshot drawn along this valley ; but there are reasons for 

 doubting the correctness of this delimitation, and for regarding the 

 beds on the north side of this valley as a repetition of the beds of the 

 Middle Division exposed ou the south side of it, though they are 

 obscured by a considerable accumulation of drift on the north side. 

 The facts are as follows : — 



(1) The Clay-bed (J^o. 9) is reached in the valley at a higher 

 level than the bottom of the valley This position of the clay is re- 

 presented in fig. 2. 



(2) A little further to the west, where the old Roman road 

 known as the Devil's Highway crosses the highroad to Wokingham, 

 a well has been recently dug to a depth of 38 feet. The mouth of 

 this well is about 240 feet above O.D., and therefore about 10 feet 

 lower than the uppermost limit of the green-sand beds (Jlo. 7 of 

 figs. 1 and 2) exposed at the northern end of the cutting. Making 

 allowance for the decoloration of the upper portion of the green 

 sand in this well-section by the action of oxj^genated rain-water, 

 there is a striking correspondence in the sands pierced by this well 

 and the sands (^os. 7 and 8 of fig. 2) which crop out on the 

 opposite side of the valley ; the green staining of the sand increased 

 in intensity with the depth of the well ; lignite in a fragmentary 

 state abounded in it, especially in the lower portion; and at the 

 bottom of the well laminated clay was found, \i\e that of bed ISTo. 9 

 in figs 1 and 2. 



(3) In the shallow cuttings of the railway, both north and south 

 of the Xine-mile Ride, the bed exposed agrees in character with 

 the bed No. 4 in fig. 2, and upon it a pebble-bed is found to rest 

 (especially weU. seen in an old ballast-pit adjoining the railway), as 

 the pebble-bed No. 3 does in the section represented in fig. 2. The 

 pebble-bed at this spot is about 210 feet above O.D level. 



(4) The brook-section west of the railway (though obscured very 

 much by peat-deposits) shows here and there clay similar to that 

 found in the bed No. 5 of fig. 2, at a height of 200 feet. 



(5) Yery near to this, an extensive lake-excavation, recently 

 made, was chiefly in a loamy sand, reaching a laminated and green 

 bed at its deepest part, at levels corresponding with those just 

 described (3, 4). 



(6) Half a mile to the west a hill in the midst of the pine-woods 

 has been excavated for rifle-targets at about 210 feet above O.D. 

 Loamy sands, with seams of pipe-clay, are exposed here with a dip 

 of nearly 5° to the north. 



(7) A third of a mile to the west of the rifle-range on the north 



