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N Buckinghamshire from the valley of the Great Ouse on the north to that of the Thames on the south there are outcrops of a series of geological formations, which are tilted gently towards the south-south-east. Through the northern belt range portions of Jurassic strata which serve to connect the county with midland regions. There we find traces of the Lias, with uplands of Oolitic limestone or stone-brash, and a broad vale of Oxford and Kimeridge Clays, modified towards the south by outlying hills of limestone capped by Cretaceous sands and clays. Still further south we come to the vale of Aylesbury which is largely formed of Gault clay; and this is succeeded in the central part of Buckinghamshire by the bold Chalk range of the Chiltern Hills, which, forming part of the London Basin, slope gently south-eastwards, and are eventually covered by Eocene deposits and by the gravels of the Thames valley.

Throughout the entire area there are various superficial deposits on hill and in vale, which help to diversify the soils of this essentially agricultural county.

Of the industries directly connected with the geology, those of lime-burning and brick-making are the principal; but changes here, as elsewhere are in progress. The smaller brickyards cannot compete with the larger, while the local road-mending materials have given place to more durable stone obtained from a distance; hence in remoter regions there are fewer pits or 'geological sections' than was formerly the case, and except as lime-works many small quarries have been abandoned. A striking instance of the changes is noted by Mr. A. Morley Davies, who, in writing of the Thame valley in 1898, says: 'Now however the stone-pits seem all abandoned and mostly levelled over; the only one I saw was being used to store Leicestershire road-metal.'

Phosphatic deposits were formerly worked, but owing to foreign competition the industry is being gradually extinguished in this country. Elsewhere the market and nursery gardens of the Thames valley, the dairy lands of Aylesbury, and the beech woods used for chair-making at High Wycombe, give rise to occupations due more or less directly to the nature of the soil.

The county is one which is by no means devoid of interest to geologists, and our knowledge is especially associated with the names of