I. GEOLOGY. 819 



3252f. Geological Map of Mid Wales, on the scale of one 

 inch to a mile. 



This map contains 17 quarter sheets, on the scale of one inch to one mile. 

 It comprises part of the Silurian rocks of Wales, and the Old Bed Sandstone 

 of Herefordshire and Shropshire. Kocks of Lower Silurian age occur in the 

 western portion of the district, the north-western area displaying intrusive 

 and interbedded igneous rocks. To the S.E. there is a succession of beds of 

 Upper Silurian and Old Red Sandstone age, while to the 'N.E. Lower 

 Silurian rocks crop out, together with a small exposure of the Cambrian 

 rocks in the neighbourhood of Church Stretton. A portion of the Shrop- 

 shire coalfield is included in the N.E. part of the map, and also the over- 

 lying Permian and Triassic formations of Shrewsbury. The localities where 

 lead ores occur are indicated by the usual symbols. 



3252g. Geological Map of the Midland Counties, N.W. 



Division. Six sheets ou the scale of one inch to one mile, mounted 

 together. 



The Carboniferous Limestone of Derbyshire, coloured pale blue on the map, 

 occupies almost the central portion. The interbedded basalts (Toadstones) 

 are shown, and also the metalliferous lodes (mostly lead ores). 



This tract is traversed by the Pennine anticlinal axis from which the strata 

 dip away to the east and west, the Yoredale Shales, Sandstones, and Lime- 

 stones, and the Coal Measures, appearing successively on either side. To the 

 eastward these form the Nottinghamshire and Yorkshire coal-fields, and" are 

 overlaid by Permian Sandstone, Magnesian Limestone, and various Triassic 

 strata, but they are cut off to the westward by the boundary fault, which 

 running nearly N.N.W. by Congleton brings the Carboniferous Limestone 

 against the Trias. Near Stockport the Coal Measures reappear as the con- 

 tinuation of the Lancashire coalfield ; and further south, near Stoke-on-Trent 

 and Newcastle-under-Lyne in the N. Staffordshire coalfield, south of the 

 limestone tract, the Carboniferous rocks are concealed by Triassic beds, but 

 they reappear in the Leicestershire coalfield, part of which is seen in the S.E.. 

 corner of the map. Towards the west a large area is occupied by the Triassic 

 Marls of Cheshire, in which extensive deposits of rock-salt occur. 



3252h. Geological Map of the Midland Counties, S.E. 



Division.- Six sheets, on the scale of one inch to one mile, mounted 

 together, illustrating the geology of the whole or parts of nine 

 counties in central England. 



The Oolitic rocks cross the map diagonally from N.E. to S.W. The strata 

 in which the Northamptonshire iron-ores are worked are indicated on the 

 map. Towards the S.E. these limestones and sandstones are succeeded by 

 the Oxford Clay, which, after forming the flat districts around Huntingdon 

 and Bedford, passes beneath a second escarpment of the Cretaceous rocks, 

 running roughly parallel to the first. A small portion of the Lower Tertiaries 

 of the London basin occurs in the S.E. corner of the map. To the N.W. of 

 the Oolitic feature the Lias and Trias form the broad undulating country of 

 Leicestershire, while in the N.W. corner of the map a great part of the 

 Warwickshire and Leicestershire coalfields are shown. 



3252k. Geological Map of the Lancashire Coalfield, 



scale six inches to one mile. 



The area comprised in the sheet includes on the north Preston and Burn- 

 ley, and on the south St. Helens and Manchester. 



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