8 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 21, 



539 feet. The supply of water from this source being found insuffi- 

 cient for their purpose, the Directors of the Company, in 1852, con- 

 sulted MM. Degousee and Laurent, the eminent well-engineers of 

 Paris, on the advisability of sinking through the Chalk into the 

 Lower Greensand. In November of that year these gentlemen came 

 to London, and I accompanied them to those places in the neighbour- 

 hood of Merstham and Reigate where the outcrop of the chalk and 

 underlying clays and sands is best exposed. The conclusion to which 

 they arrived was precisely similar to my own, and on their report 

 the Directors resolved to undertake the work. Accordingly, on the 

 10th of June, 1853, boring was commenced in the chalk at the bot- 

 tom of this well. 



At a depth of 569 feet from the surface the chalk with flints ended ; 

 greyish chalk without flints, becoming more argillaceous in descend- 

 ing, was then traversed for a thickness of 294 feet. (See the sectional 

 list of strata traversed by the boring, pp. 13 & 14.) The chalk-marl next 

 succeeded, and continued for 47|- feet. This would give a total thick- 

 ness to the chalk of 586 feet. The chalk-marl passes so insensibly 

 into slightly sandy marls representing the Upper Greensand, and 

 these into the Gault, that it is difficult to draw any satisfactory lines 

 of division. I have taken as the representative of the Upper Green- 

 sand the more arenaceous and chloritic beds. They are 72^ feet thick. 

 These strata, however, were here, on the whole, so argillaceous that 

 they were not permeable, and they consequently afforded no additional 

 supply of water. The Gault was found underlying the Upper Green- 

 sand in the usual order, and presented the ordinary character of a fine 

 grey calcareous clay, 130^ feet thick. i\.t the base of this mass of 

 clay a layer full of the phosphatic nodules, so common at the base 

 of the Gault at Folkestone and elsewhere, was met with. 



Thus far all the strata were in regular succession, and there was 

 every reason to believe that the same order which prevailed at their 

 outcrop, and with which there seemed to be nothing to interfere, would 

 be continued underground ; and that after traversing this band of 

 phosphatic concretions, the light- coloured siliceous sands of the 

 Lower Greensand would succeed. The ordinary probabihties of the 

 geological sequence being maintained throughout this central area 

 seemed then so strong, that when the works were at that point, just a 

 year since, having occasion to speak on the subject at the Institute 

 of Civil Engineers, I did not hesitate to express my conviction that 

 a very few more turns of the auger would tap these sands. This 

 opinion has unfortunately proved incorrect. Instead of meeting 

 with loose sands, the next bed which presented itself was one of red 

 argillaceous sand and sandstone, 1 foot thick : 1 2 feet of red clays 

 (some mottled light bluish-green) and sandstones then succeeded ; 

 followed by a singular conglomerate, 2 feet thick, containing pebbles, 

 of a considerable size, of various old and crystalHne rocks : amongst 

 these were dark grey syenites, greenstones, red clay stone-porphyry, 

 trap-rock, a grey semitranslucent quartz or hornstone, and a granular 

 schist with traces of fossils. Then came 26 feet of red clays, underlaid 

 by red saud md a bed of small rolled pebbles. These were followed 



