A HISTORY OF LEICESTERSHIRE maximum thickness to the west of the county of about 1,000 ft., but they thin out very rapidly eastwards, and are not present at Ashby-de-la-Zouch or anywhere to the east of that town. They are most strongly developed about Measham and Donisthorpe ; there is also an outcrop at Boothorpe and on the banks of the Trent at Castle Donington. When a sufficiently large area of these beds is exposed they form a dry but rather poor soil disposed in rounded gravelly knolls, which considerably add to the beauty of the scenery. KEUPER SANDSTONE The Keuper Sandstone has an average thickness of about looft., but it passes so gradually into the marls above that it is difficult to separate the one from the other. It consists of massive beds of soft sandstone, sometimes white, but usually stained red or brown. These sandstones are split up by numerous beds of marl ; they are generally false-bedded and frequently ripple-marked. In the neighbourhood of the Charnwood Hills, about Thringstone, and also at Heather and other places, the base of the sandstone contains many quartz pebbles and angular fragments, and occasionally hard beds of conglomerate. Near Castle Donington footprints of Labyrinthodon have been found in these beds, but fossils are extremely rare. 1 The sandstones have been used as a building-stone to some extent, but the rock is too soft in this district to be of much value. The Keuper Sand- stone is a valuable water-bearing stratum, and large supplies are obtained from it at Coalville, Ellistown, and other places. The outcrop of the rock extends along the western portion of the county from Appleby by Measham and Normanton to Ashby-de-la-Zouch. North of this it spreads out, covering Pistern Hill and most of the high ground between Woodville and Coleorton. At Thringstone it is thrown down by the large fault bounding the Coalfield, along the north side of which it forms a conspicuous escarpment as far as Staunton Harold, where striking to the north the escarpment is continued to Melbourne, and along the bank of the Trent to Castle Donington. The Keuper Sandstone usually forms a light and dry soil, but the outcrop in this district, when free from Drift, is too narrow to have much effect on the land. KEUPER MARL The Keuper Marl covers the whole of that part of the county west of Leicester with the exception of the small areas of older rocks which have been previously mentioned. It forms an undulating plain mostly under cultivation, of which the greater part is arable land well suited to the growing of corn. The strata consist of red and mottled marls with thin beds of grey and white sandstone, known as ' skerry.' Thin beds of gypsum occur at intervals throughout these marls, especially in the upper part, where one bed has a thickness of from 6 ft. to 1 2 ft. The sandstones are frequently ripple-marked, and contain pseudomorphous crystals of salt. Near Leicester a thick bed of soft white sandstone occurs in the upper part of the marl, but 1 Memoirs of the Geol. Sxrr. .- The Leicestershire Coalfield,' 62. 10
