AND BAGSHOT BEDS OF ALDEESHOT. 



439 



butts are at 450 feet ; and this gives 100 feet above the hill by the 

 Aldershot brickyard, shown in the section (fig. 3), which is capped 

 on the line of the section by some 15 or 20 feet of Lower-Bagshot 

 beds. This 100 feet would bring us into the lower beds of the 

 Middle Bagshot in their natural position, and this disposes of 

 anything unusual in their occurrence at Caesar's Camp. 



Coming now to the London Clay in this section, I have already 

 shown how the base of the clay, as proved in the South-Camp and 

 Aldershot- Waterworks borings, agrees with both the proved and 

 measured dip of the Bagshot Beds; I will now show that the 

 thickness of the London Clay at the latter place is about the same 

 as that at the South- Camp boring, and at Ash, as I have given it 

 above. This I shall do, since Mr. Irving (Quart. Journ. Geol. Soc. 

 vol. xli. p. 507), in his " General Conclusions," No. 6cZ, points to 

 this as a section proving great erosion of the London Clay before 

 the deposition of the Bagshots. Two borings at the Aldershot 

 Waterworks penetrated the London Clay 132 and 134 feet respec- 

 tively. I will take a mean of 133 feet. The mouth of the well is 

 at 250 feet O.D., and the outcrop of the London Clay is at an 

 altitude of about 340 feet, and is 730 vds. 1ST. Now 730 yds. and 

 a dip of 2^° N. gives a rise of 110 feet ; so we have a total thicknesss 

 of (133 -{-9 0 + 1 10) =333 feet, which agrees with the deep boring 

 at South Camp (332 feet), and with the thickness at the South- 

 western Railway Station at Ash (330 feet). 



There are two more well-sections which should be mentioned in 

 connexion with this area, namely those given in Geol. Surv. Mem. 

 pp. 445 and 446, as at Aldershot Place. (This I think must be 

 meant for Aldershot Park, as it is called on the 6-inch Survey maps, 

 Aldershot Place being called there " Manor House." The descrip- 

 tions of the positions and altitudes of the wells agree well with 

 spots in Aldershot Park, but cannot be reconciled with any part of 

 the Manor-House grounds.) When the depths of London Clay 

 found in these borings, namely 151 feet in one and 66 feet in the 

 other, are plotted in connexion with the thickness of London Clay 

 found at the D Lines, South-Camp well, they are found to give a 

 dip of between 2|° and 3° to the N., and a thickness of 330 feet. 



Thus we get a thickness of London Clay equal to that at Aider- 

 shot Waterworks, South Camp, and Ash, and a dip of the strata 

 intermediate in amount between Aldershot and Ash, between which 

 two places Aldershot Park occupies a nearly central position. The 

 Heading Beds with 76 feet are also of about the usual thickness. 



Coming now to Caesar's Camp and the Long Valley, there is but 

 little of importance besides the occurrence of the green sands at 

 altitudes of from 500 to 550 feet and even higher. The Middle- 

 Bagshot beds can be traced all across the valley, overlain occasionally 

 by Upper-Bagshot sands, with their uppermost limit marked here 

 and there by the pebble-bed. 



So far, each section has been discussed to see to what extent it bears 

 out the hypothesis of a constant northerly dip of the beds. I will 

 now shortly describe a section taken from North to South, across the 



