BAGSHOT STRATA PROM AIDEESHOT TO WOKIXGHAM. 499 



immediately to the south of it the pebble-bed, intermingled with a 

 few snbangular fragments of the later drift, and probably somewhat 

 reconstructed, is exposed at the surface, many of the pebbles being 

 very large (4 to 6 inches in length). A little further south, at the 

 College Pig Farm, the same bed was found intact, with a thickness 

 of about 3 feet, so recently as last year, and worked for gravel. 

 The bed there was simply a mass of rounded flint-pebbles imbedded 

 in sand. On the west of the railway, to the south of Amburrow 

 Hill, it has been again exposed in excavations recently made for 

 building-purposes, and it is well exposed in the grounds of Sand- 

 hurst Lodge, the residence W. J. Farrer, Esq., F.G.S. 



The height above O.D. level of the Middle Bagshots at the 

 Wellington well-section will be seen from an inspection of fig. 1. 

 The upper pebble-bed, for example (no. 3), is there found at a 

 height of about 260 feet; and in the sections just described its 

 height ranges (owing to dip) from about that height to 250 feet. 

 These observations as to altitudes, it may be remarked, are taken 

 (as are all the heights mentioned in this paper) from the Ordnance 

 Map of the district, constructed on the scale of 6 inches to the mile. 



2. Wellington College Lakes. — The 250 feet contour-line passes 

 along the margin of the lowermost of these lakes, which have been 

 formed by simply damming up the natural drainage of the valley ; 

 and the same line passes close to the railway-station. Last year an 

 extensive excavation for the new swimming-basin exposed the 

 pebble-bed just below the level of the water, at a height above O.D. 

 level of 250 feet. Below this (which was of the same character as 

 is exhibited by it in the railway-cutting to the north of the station) 

 there was exposed from six to eight feet of yellow loam ; and beneath 

 this again the green clayey bed is exposed in the open water-course 

 by which the lake may be drained. There is no difficulty in 

 identifying the beds here exposed with those of Nos. 3, 4, and 

 5 of figs. 1, 2 ; and the continuity of the green loamy sand bed 

 between these two places has been proved in recent excavations. 

 On both sides of the lake a stiff yellow loam (almost, in fact, a clay) 

 occurs above the pebble-bed (J^o. 3), as it commonly does at the base 

 of the Upper Bagshots above the pebbles (c/. ante), 



3. Torh Toiun and Camherley. — Here some extensive drainage- 

 works have been constructed during the last two years. The main 

 sewer follows the turnpike road. It commences where the road 

 passes over the shoulder of the Obelisk Hill, at a height of some 

 §20 feet. As the excavation descended the hill, it exposed nothing 

 but the usual buff-yellow sands of the Upper Bagshots, until the 

 altitude of about 260 feet was reached. At this level the sands were 

 found passing down into the usual yellow clayey bed, and bcDeath 

 this a bed of flint pebbles was passed through. Below these pebbles 

 a yellow loamy sand was passed through till the level of 247 feet 

 was reached, when this passed into a green bed of clay and sand, of 

 about ten feet in thickness. Below this the excavation was con- 

 tinued in loose green sand, the bottom of which was not reached. 



The correspondence in thicknesses and altitudes of the beds here 



