Page:VCH Worcestershire 1.djvu/47

 GEOLOGY the local supplies of water to the villages and farm-houses, sources which are liable to pollution in populous places through surface con- tamination. Pseudomorphous crystals of rock salt have been occasionally found in the Keuper Sandstones, while in the Keuper Marls the presence of rock salt is indicated by the occurrence of brine springs. These springs in Worcestershire have been known since the Roman occupation, but the deeper-seated and stronger springs were not proved until much later, that of Droitwich in 1725, and Stoke Prior in 1829. At Stoke Prior a shaft was sunk and a small amount of rock salt obtained ; subsequently a boring was carried to a considerable depth. At Droit- wich a shaft has been sunk 80 feet and a boring carried to a total depth of 210 feet through soil, drift, red marl and gypsum, and red marl with rock salt. Here as at Stoke Prior the deeper borings now extend to about 1,000 feet. At both localities the brine is copious, and when not kept down by pumping, it rises to the surface. At Droitwich the town and neighbourhood have been affected by the pumping from the brine- pits, and subsidences have occurred through the loss of material under- ground.' H. E. Strickland in 1842 drew attention to some old salt works on DefFord Common, mentioning that seventy years previously (about 1770) a shaft was sunk to a depth of 175 feet, and that brine then over- flowed. The lowest bed penetrated was the grey marl of the Triassic series, which occurs on top of the red marl.^ Saline water has been encountered at Aberton, north-east of Pershore, the village being situated on a faulted junction between the Red Marl and Lower Lias. A salt well to the south of Dudley, known as Lady Wood Saline Spa, is situ- ated on the Coal Measures. The red marls and sandstones were deposited in desert regions with inland salt lakes, the area being subject to wet and dry seasons ; in the former the clayey or marly sediments were laid down, in the latter the rock salt was precipitated.^ It is not unlikely that some of the sandy Triassic layers were drifted by winds, especially those which are re- markably false-bedded. On top of the Keuper Marls we find a series of passage-beds which connect the Triassic with the Liassic formations. These are the Rhatic Beds, so named from the Rhstian Alps in the Tyrol, and they indicate the incoming of marine conditions, perhaps locally in the form of a large inland sea like the Caspian. The Rhsetic Beds occur in the outliers south of Upton-on-Severn, and at Bushley on the right bank of the Severn. Their main outcrop lies on the left bank of the Severn from Hill Crome northwards to Norton near Worcester, and Dunhampstead, where the beds are shifted by faults. They occur also north and west of ' See T. Ward, Trans. Manchester Geol. Soc, vol. xviii. p. 396. I 17 C
 * J. Dickinson, Report on Landslips in Salt Districts, 1873.
 * Proc. Geol. Soc, vol. iii. p. 732.