The water supply of Bedfordshire and Northamptonshire, from underground sources: with records of sinkings and borings / by Horace B. Woodward ... and Beeby Thompson ... with contributions on rainfall by Hugh Robert Mill.

  • Woodward, Horace B. (Horace Bolingbroke), 1848-1914
Date:
1909
Catalogue details

Licence: In copyright

Credit: The water supply of Bedfordshire and Northamptonshire, from underground sources: with records of sinkings and borings / by Horace B. Woodward ... and Beeby Thompson ... with contributions on rainfall by Hugh Robert Mill. Source: Wellcome Collection.

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    bands and nodules of limestone; the lower includes the “ Blue Lias ” limestones and clays or shales, an alternating series of comparatively thin bands, with at the base a mass of clays locally as much as 60 feet thick. . . The thickness of these sub-divisions may be estimated as follows:— „ Feet. Lower Lias Clay - about 350 Lower Lias Limestones and Clays - - about 150 about 500 The upper sub-division is not water-bearing. The lower sub- division is not exposed in our district; from it limited supplies of water are obtained in other regions generally near the outcrop. Mr. Thompson observes that the actual total thickness of the Lower Lias in Northamptonshire is not known with certainty, because the junction of the zone of Ammonites margaritatus (base of Middle Lias) with that of Ammonites capricornus has not been determined in any of the deep borings.. He adds that within the county of Northampton where borings have been made, the limestone-beds of the lower part of the Lower Lias are not such a conspicuous feature as they are about Kugby, and no water is yielded by any part of the Lower Lias. Middle Lias. By B. Thompson. The Middle Lias of Northamptonshire is about 100 feet thick, and may be divided into three main portions Ammonites spinatus Zone. Upper Ammonites margaritatus Zone 1. The Marlstone or Middle Lias rock-bed. A calcareous, or sandy, or ferruginous bed. The zone is represented by two or more thin hard beds with intervening clays in some places. 2. Alternating thin hard and thicker soft beds; micaceous sandstones, or marlstones, and micaceous sandy clays, with a well marked mottled rock-bed at the base containing pebbles and rolled fossils. Lower Am. margaritatus Zone or Am. nitescensZonQ 3. Calcareous, sandy, micaceous clays with hard beds at intervals, and a well marked pebble bed at the base containing rolled fossils. The two upper divisions, which together are only 21 feet thick at Northampton, are about 40 feet thick in the western parts of the county, and constitute the most important part of the Middle Lias from the point of view of water-supply. Water supply from the Middle Lias of Northamptonshire is a complicated problem. The so-called Marlstone, or rock-bed, the uppermost bed of the Middle Lias, is the most reliable source of water over a large area, but in certain directions it fails. Where it fails lower hard rocks may take its place in yielding water, but in an untried area there is no certainty that they will. Actually five distinct horizons, at least, in the Middle Lias yield water, but not more than four have been detected in any