Figs. 251-253.
Well at Charrington’s, Mile End.

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Norwich.—Well at Coleman’s works. After a few feet of alluvium the borer passed through hard chalk with flints at distances of about 6 or 7 feet apart, for 700 feet, with the exception of 10 feet at the depth of 500 feet where the rock was soft and of a rusty colour, thence the flints were thicker, namely, about 4 feet apart to the depth of 1050 feet. After this 102 feet were pierced of chalk, free from flints, to the upper greensand, a stratum of about 6 feet, and then gault for 36 feet. The whole boring being full of water to within 16 feet of the surface.

Section of strata;—

Feet.
Alluvium12
Hard Chalk, with flints483
Soft Chalk10
Hard Chalk190
Hard Chalk, flints closer350
Chalk without flints102
Upper Greensand6
Gault36
Total1189

Paris.—The wells sunk in the Paris basin, of which [Fig. 254] is a section, are very numerous, and many of them of great depth. [Fig. 255] is a plan indicating the position of the principal wells, and [Figs. 256 to 258] sections giving each a summary of the nature and thickness of the formations passed through.