Chelmsford.—The well belonging to the Local Board of Health, situated at Moulsham, yields about 95,000 gallons of water a day. It is sunk for 200 feet; the rest bored. Water overflowed at first, but now that the well is in use and pumped from, the water only rises to 76 feet from the surface. The following strata were pierced;—
Cheshunt, New River Company.—Situate at the engine-house between the two reservoirs. The well is 171 feet deep, and is steined partly with brickwork and partly with iron cylinders. For 12 feet in depth the well is 11 feet 6 inches in diameter, and steined with 14-inch brickwork; for a farther depth of 44 feet it is 9 feet diameter, and steined with 9-inch brickwork; of the 44 feet, 41 feet are lined with cast-iron cylinders, 8 feet diameter, which are also carried to a depth of 105 feet from the surface. There are fifteen cylinders of this size in use, and they are succeeded by others 6 feet 10 inches diameter, of which there are six in use; these are again succeeded by two cylinders 6 feet diameter. The whole of the cylinders are 6 feet in depth. The bottom of the last cylinder is 118 feet from the surface, at which point they rest upon a foundation of 9-inch brick steining 7 feet in depth. At the bottom of the 6-feet cylinders the well widens out in the form of a cone 12 feet 6 inches diameter at the floor, which is 26 feet below the bottom of the 6-feet cylinder. In the centre of the well a bore-hole, 3 inches diameter and 27 feet deep, was made, and the well is provided on the floor-level with headings.
| Section of Strata. | Feet. In. |
| Surface Earth | 1 6 |
| Gravel | 8 0 |
| London Clay, 47 feet;— | |
| Blue Clay | 45 0 |
| Yellow Clay | 2 0 |
| Reading Beds, 51 feet;— | |
| White Sand | 12 0 |
| Dark Sand | 39 0 |
| To Chalk | 107 6 |
| Chalk | 63 6 |
| Total | 171 0 |
Dorking, Surrey, obtains its water supply from a well sunk into the outcrop of the lower greensand, at the south side of the town. The shaft is 11 feet in diameter and 160 feet deep, steined with 9-inch work laid dry. The yield is not more than 30 gallons a minute, owing to the unfortunate position of the well, but might be considerably increased if suitable means were adopted.
Harrow Waterworks.—The well is situate 430 yards to the west of the church. The surface of the ground is 226 feet above the Ordnance datum. There is a shaft for 1931⁄2 feet; the rest is a bore. In a bed of dark red sand 144 feet down, the water was very foul. Strata;—
| Feet. In. | |
| Light Blue Clay, with light-coloured stone | 19 11 |
| Brown Clay, with white stone | 54 11 |
| Dark Mottled Clay | 15 0 |
| Similar Clay, with dark and green sand | 4 0 |
| The same, very hard | 3 0 |
| The same, very hard, and dark sand | 2 0 |
| Lighter-coloured Hard Clay | 5 0 |
| The same, and dark sand | 6 0 |
| Large Pebbles | 0 6 |
| Clay and Sand | 5 0 |
| Light Blue Clay | 0 4 |
| Light-coloured Stone, with red and blue spots | 1 3 |
| Mottled Clays | 7 11 |
| Yellow, Light Blue, and Green Clay | 1 0 |
| Dark Green Clay, with black veins and spots | 5 0 |
| Blue Clay | 1 6 |
| Very Hard Brown, Yellow, and Blue Clay | 4 0 |
| Light Brown Running Sand, with water | 2 6 |
| Hard Mottled Clays | 6 6 |
| Light Brown Dead Sand | 8 8 |
| Black Peat, with dark pebbles | 0 6 |
| Brown and Green Gravel, with flints | 3 2 |
| Green Clay | 0 4 |
| To Chalk | 158 6 |
| Chalk, with beds of flint 4 to 15 inches in thickness, 15 to 24 inches apart; 3951⁄2 feet down, from surface, a bed of flint 6 feet thick | 254 0 |
| Total | 412 6 |
Water rises to a height of 125 feet below the surface. The yield is about 190 gallons a minute.