Description of the Strata .—The Brick-pit at Lexden is situated on a plateau upon the south side of the valley of the Colne, about a mile west of Colchester. The table-land around Colchester, elevated somewhat more than a hundred feet above the level of the sea, upon the south side of the Colne, consists of thick beds of gravel and sand resting upon London Clay. This gravel is for the most part well rolled, and its stratification is very regular. Its upper and lower portions are stony, while the middle consists principally of false-bedded strata of sand. Fine sections are exposed by the drainage-works now going on at the new cavalry-barracks at Colchester, and in pits in the suburbs. The lowest bed, resting on the London Clay, is a coarse gravel, well seen at Wivenhoe ballast-pit. I believe this extensive bed of gravel to be the old gravel which elsewhere underlies the Boulder-clay. It crops out towards the southern part of Essex, ranging from Danbury, where it attains a considerable elevation, by Tiptree Heath to Colchester. It is seen near the railway-station at Hadleigh in Suffolk, and in the same county forms an extensive heath near Dunwhich.