_Durham._--Large quantities of water are pumped from the lower Permian sandstone beneath the magnesian limestone of this county, and are used for the supply of the towns of Sunderland, South Shields, Jarrow, and many villages. The quantity, calculated by Daglish and Foster to reach five millions of gallons a day, is obtained from an area of fifty square miles overlying the coal measures. The water-level has not been lowered in the rock by these operations. Along the coast it is that of mean tide, and inland rises to a level of 180 feet. In the coal measures below there is little water, and that little is saline. Sedgwick gives the strata as red gypseous marls, 100 feet; thin bedded grey limestone, 80 feet; red gypseous marls, slightly salt, 200 feet; magnesian limestone, 500 feet; marl slate, 60 feet; lower red sandstone, 200 feet. _Coventry._--Warwickshire. The town is supplied with 750,000 gallons of water a day from two bore-holes made in the bottom of the reservoir. The bore-holes are respectively 6 inches and 8 inches diameter, and 200 feet and 300 feet deep. The town is situated on the Permian formation, but Latham states that the supply is procured from the red sandstone, and, from observations made, it has been found that the two bore-holes yield water at the rate of 700 gallons a minute. TRIAS STRATA. _Birkenhead._--There are here several deep wells belonging to the Tranmere Local Board, the Birkenhead Commissioners, and the Wirral Water Company, yielding together about 4,000,000 gallons a day. Figs. 222, 223, show a section and plan of the No. 2 or new engine well at the Birkenhead Waterworks. The shaft is 7 feet diameter for 105 feet, with a bore-hole 26 inches for 35 feet, 18 inches for 16 feet, 12 inches for 99 feet, and 7 inches for 150 feet, or a total depth from surface of 405 feet. The water-level is about 95 feet from surface when the engine is not at work. At the upper water-level, shown in the 26-inch hole, the yield was at the rate of 1,807,400 gallons in twenty-four hours, at the lower level at the rate of 2,000,000 gallons in the same time. At the water-level indicated in the 7-inch bore, water was met with in large quantities. The old engine well is almost identical. [Illustration: NEW ENGINE WELL, BIRKENHEAD WATERWORKS. Fig. 222.] [Illustration: PLAN. Fig. 223.] [Illustration: Fig. 224. WELL AT ASPINALL'S BREWERY, BIRKENHEAD.] [Illustration: Fig. 225. PLAN] [Illustration: Enlarged Parts. _at_ A. A. _at_ B. B. _at_ C. C. _at_ D. D. _at_ E. E. Fig. 226.]