A HISTORY OF NORTHAMPTONSHIRE grains of solid matter per gallon, also it is very moderate in quantity, 100,000 to 200,000 gallons per day from a single well or boring. The water rises 535 feet from a depth of 436 feet below sea-level, taking an average of the four places where it has been encountered. The Middle Lias may yield water from any of its hard beds, as already pointed out. In the western parts of the county, at and around Catesby, No. 7, typical section, yielded much water when cut through in making Catesby tunnel of the G. C. Railway, but is the only place to be quoted. Bed 5 is generally reliable in the western parts of the county, and supplies numerous springs ; it yields water as far eastward as Northampton. By far the most reliable source of water is the rock-bed. No. I, this supplied Northampton with water, by an artesian well, for forty years ; it has been tapped as far eastward as Kettering and Finedon, but all deep borings into it southward and eastward of the Nene have been failures. The Upper Lias must be classed as impervious, though the lower beds, 6 to 1 1 (typical section) may yield a little water, as also No. 3. The Northampton Sand yields abundance of good water from hun- dreds of springs and wells, but superficiality and consequent weathering of the rock seem to be necessities for quantity and good quality. As a deep- seated source of water it is decidedly a failure, for in easterly districts where it has been pierced at a good depth, water is absent or small in quantity (Peterborough), or highly sulphurous, emitting an offensive odour of sulphuretted hydrogen (Raunds, etc.). The Lower Estuarine Beds and Variable Beds (3 and 4 of typical section) may be regarded as feeders of the lower bed generally, but the upper one, 3, does sometimes appear to be an independent source (Hardwick). The Lincolnshire Oolite may be classed as a fairly good water-bearing formation, but un- less its junction with the less permeable beds beneath is lower than adjacent valleys, it is liable to run itself dry like the Great Oolite Limestone. The Great Oolite formation may yield water at three separate horizons (see typical section, p. 9), the thick limestone bed being the chief source, but as this is not sufficiently porous throughout to retain the water, but only holds it in quantity in the joints and fissures, it is most unreliable for a public supply ; great springs issue from it soon after heavy rainfall which in the summer may cease entirely. In favour- able situations with respect to adjacent valleys it will yield a permanent supply. The Cornbrash yields fairly good water, but the rock is too thin to have any extended catchment area or storage capacity. The Drift Gravels and Sands are very porous, they absorb water freely and discharge it freely, and so easily run dry, except in a valley or depression in other rocks ; still many places utilize the water from these beds. The River Gravel holds a vast quantity of water, and but for its usually polluted condition, partly because stagnant as an underground lake, and partly from particular pollution from various sewage farms along the Nene valley, would be a valuable source of water. 38
