READING AND THANET SAND, 85 feet;-- Mottled Clay 25 " Coloured Sand 60 " ---- To Chalk 199 " CHALK 50 " ---- Total 249 " ---- _Kentish Town._--This well was sunk under the supposition that as the outcrop of the subcretaceous formations was continuous around the margin of the cretaceous basin surrounding and underlying the London tertiaries, except at the eastern border, those subcretaceous formations would be found under London, just as they actually were at Paris. This proved to be the case until the gault was passed, when a series of sandstones and clays was encountered, occupying the place of the lower greensand, but evidently of older geological character, and having many of the features of the new red sandstone. [Illustration: BORING AT KENTISH TOWN, LONDON. Figs. 246. 247.] The surface of the ground, Fig. 246, is 174 feet above Thames high-water mark. There is a shaft for 539 feet; the remainder being bored. The following detailed account of the strata is due to Prestwich. [Illustration: BORING AT KENTISH TOWN, LONDON--_continued_. Figs. 248, 249.] LONDON CLAY, 236 feet;-- Feet. In. Yellow Clay 30 6 Blue Clay, with septaria 205 6 READING BEDS, 61-1/2 feet:-- Red, Yellow, and Blue Mottled Clay 37 6 White Sand, with flint pebbles 0 6 Black Sand, passing into the bed below 2 0 Mottled Green and Red Clay 1 0 Clayey Sand 3 0 Dark Grey Sand, with layers of clay 9 6 Ash-coloured Quicksand 6 6 Flint Pebbles 1 6 THANET SAND, 27 feet;-- Ash-coloured Sand 10 0 Clayey Sand 4 0 Dark Grey Clayey Sand 11 0 Angular Green-coated Flints 2 0 CHALK, WITH FLINTS (? UPPER CHALK), 244-1/2 feet;-- Chalk, with flints 119 6 Hard Chalk, without flints 8 0 Chalk, softer, with a few flints 31 6 Nodular Chalk, with three beds of tabular flints 13 6 Chalk, with layers of flint 32 6 Chalk, with a few flints and patches of sand 9 6 Very Light-grey Chalk, with a few flints 30 0