Vol.50.] BOEINGS AT CULFORD, WINKFIELD, WARE, ASTD CHESHUNT. 409 



The Lower Chalk is rather thick, and the whole formation of the 

 Chalk is about 80 feet thicker than under London and 55 feet 

 thicker than at Richmond. So clayey aro some of the specimens 

 from the Chalk Marl that we were at first inclined to think, as also 

 was Mr. W. Hill, that the Gault might have been reached, and 

 therefore that the Upper Greensand was absent — a view that 

 was of course negatived when the last-named formation was found 

 to occur still lower. A specimen from 927 feet was submitted to 

 Mr. "VV. Brierley (of Southampton), who reports that it is composed 

 of 62* 1 per cent, of calcium carbonate, with a small quantity of iron, 

 etc., and 37*9 per cent, of clayey matter — a composition not varying 

 much from that of some highly calcareous Ganlt. 



The Upper Greensand seems to have been reached at about 

 939 feet, when the boring entered a sandy marl : this may be 

 from 6 to 10 feet thick, and is underlain by impure malmstone. A 

 specimen of the latter, from 956 feet, is sandy and has the same 

 structure as a calcareous malmstone from Selborne, a slide of which 

 was lent by Dr. Hinde. Each contains about the same amount of 

 quartz, in very minute grains : that from Selborne, however, having 

 rather more glauconite and more foraminifera, but rather fewer 

 spicules and hardly any black specks. A calcareous malmstone 

 from Keigate, a slide of which was also lent by Dr. Hinde, has much 

 more glauconite than either of the above and more sponge-spicules. 



The Gault is very thick, being from 63 to 133 feet thicker than 

 in the deep borings in and around London, the nearest approach, 

 anywhere in the London district, being at Shoreham in Kent 

 (38 feet less), and the only excess being at Caterham, by nearly 

 80 feet. 



From a geological point of view, it is of course to be regretted 

 that the boring was not carried deeper, to prove the thickness of the 

 Lower Greensand and to find by what this formation is underlain. 

 We may perhaps venture to suggest that it is not likely that 

 Wealden beds would be found, but that any division of the great 

 Jurassic series may be represented, and that probably some Jurassic 

 formation would be passed through before the older rocks are 

 reached. 



Notes on the Water. 



The level of the water from the Chalk was 151 feet down, or only 

 67 feet above Ordnance datum. In September 1890 the supply was 

 weak, and at the end of November pumping, at the rate of 3 gallons 

 a minute, lowered the water from this source 32 feet. This poor 

 yield from the Chalk is what might be expected from a bore of small 

 diameter carried through more than 200 feet of Tertiary beds, but 

 it does not prove that the Chalk here is practically waterless. 



On May 9th, 1893, at the end of the work, the water from the 

 Lower Greensand rose to over 2| feet above the ground. This 

 water-level steadily rose, as the borehole was shelled out, and reached 

 the height of 7 feet 8 inches, or more than 225^ feet above Ordnance 

 datum, on May 18th. 



The high level to which the water from the Lower Greensand 



