314 Reviews — Geological Survey of England — Leicester. 



THANKS to the energy of the Director, Mr. J. J. H. Teall, there 

 has been a steady output of memoirs by the staff of the 

 Geological Survey, as may be seen by reference to this and to the 

 June Number of the Geological Magazine (pp. 269-277). 



In the present memoir, by Mr. C. Fox-Strangways, we have 

 a description of the geology embraced in the area contained in 

 Sheet 156 of the new series one-inch Map of England, which covers 

 parts of central and eastern Leicestershire and a part of Eutland. 

 Considerable changes have been made in the delineation of the 

 geology of this part of the Midlands, due principally to the use of 

 larger scale maps, which has enabled the outcrop of the granite and 

 other older rocks in the neighbourhood of Mountsorrel to be shown 

 with more exactness than was possible on the old maps of smaller 

 scale. The outcrop of the RhEetic beds has also been traced, and 

 slight modifications have been made in the mapping of the Keuper 

 Marl ; the subdivisions of the Middle Lias, too, are now shown with 

 greater precision. 



The Drifts, which cover so large an extent of the area embraced 

 in this map and memoir, have been surveyed in detail for the first 

 time ; they form the most striking feature of the map, and well 

 exemplify their plateau-like character. 



The alluvium, both in the main and smaller valleys, has been 

 carefully and accurately traced, and tends to bring out more clearly 

 the drainage system of the country. The river terraces are also 

 shown. 



A new feature, which will be observed on the colour-printed map, 

 is the introduction on the margin of a longitudinal section from 

 south-east to north-west, showing the general structure of the 

 ground, taking in the Charnwood rocks and Mountsorrel Granite 

 in the north-west, with the Keuper Marls about Syston, followed 

 by the Ehsetic beds and Lower Lias Limestone and shales, with the 

 Middle Lias sandy shales and rock-bed resting on it, and also 

 occasional outliers of Inferior Oolite forming the high ground of 

 Eobin-a-Tiptoe, Whatborough Hill, and other eminences (see also 

 page-section given at p. 5 of memoir). Everywhere between the 

 main valleys and their tributaries the Great Chalky Boulder-clay, 

 with intercalated beds of sand and gravel, together with the Upper 

 and Lower Older Boulder-clay, cover the country in wide sheets. 

 The district is thus essentially a clay country, the Keuper Marls, 

 Lias Clays, and Boulder-clay all contributing to its argillaceous 

 character, and influencing its soils from an agricultural point 

 of view. 



The older formations that come to the surface within the limits 

 of the map occupy a very small space, but they have been proved 

 to extend further beneath the newer rocks at Leicester and else- 

 where. They include a small outcrop of the pre-Cambrian slates 

 of Bradgate Park and the intrusive granite and other rocks of 

 Mountsorrel, which form the fringe of the Charnwood Forest 

 district. The principal formations, however, are the Trias and the 

 Lias, which practically cover the whole of the district. 



