48 The Soils of England and Wales 



edges, or abutting against them, lie the Secondary 

 strata \" 



The geological structure of the north of England is 

 mainly dominated by the great Pennine anticline, forming 

 a broad ridge of high land running north and south, and 

 sharply cut oif on the south by a great east and west fault. 

 The centre of this anticline is formed by Carboniferous 

 or Mountain Limestone, on whose flanks lie the Millstone 

 Grrit, a coarse sandstone, and then the Coal Measures, 

 which largely determine the position of the great in- 

 dustrial districts of the north. To the north-west of the 

 Pennine axis lies the mass of still older rooks forming the 

 Cumbrian (or Lake District) group of mountains. 



The west of Wales consists mainly of Cambrian and 

 Ordovician rocks, flanked on the east by Silurians, while 

 in the south is a great basin of Carboniferous rocks, 

 edged by a rim of Mountain Limestone and containing 

 the important South Welsh coalfield. The south-western 

 peninsula of England (Devon and Cornwall) consists of 

 rocks of Devonian and Carboniferous age with great 

 masses of intrusive igneous rock (largely granite). 



Isolated patches of ancient rocks occur here and there 

 in the midlands, e.g. the midland coalfields and the rocks 

 of Charnwood Forest. Here and there rocks of pre- 

 Cambrian (Archtean) age appear at the surface, but 

 their total extent in England and Wales is comparatively 

 insignificant. 



The general effect on the physiognomy and soil-charac- 

 ters of the country produced by the older rocks of the 

 north and west has already been described, and it would 

 not repay us to consider the different formations in detail. 



The limestones form an outstanding series with very 

 marked soil-characters and vegetation. By 

 far the thickest and most extensive is the 



' H. B. Woodward, The Geology of England and Wales, Second 

 edition, p. 26, 1887. 



