GEOLOGY AND SURFACE FEATUEES. 11 



bleak and treeless, as are those in the north, but they yield copper, tin, and lead, 

 and between them lie broad pasture-lands and fruitful valleys.* 



A broad expanse of comparatively level land separates the barren palaeozoic 

 mountain ranges of England and Wales from the uplands and plains which occupy 

 the entire eastern part of the country. Spreading over the whole of Central 

 England, this level tract extends along the eastern foot of the Pennine range to 

 the coast of Yorkshire, merges on the west into the wide plain of Cheshire and 

 Lancashire, and can be traced southwards into the valley of the Severn, and beyond, 

 through the vale of Taunton and other low-lying districts, to the south coast of 

 Devonshire. Nearly the whole of this extensive region is occupied by the sand- 

 stones, limestones, clays, and marls of the triassic and liassic formations, the 

 harder of these rocks often rising into minor escarpments facing westwards, and 

 overlooking rich undulating meadow lands and cultivated fields. 



On the east these plains and undulating grounds are bounded by an oolitic 

 limestone range, which traverses England from the coast of Dorsetshire to the 

 estuary of the Tees, presenting a bold escarpment towards the west, on ascending 

 which we find ourselves upon an undulating table-land, mostly occupied by sheep 

 pastures. The Cotswold Hills, which bound the vale of Gloucester, and the 

 moorlands of Yorkshire, far away in the north, both belong to this formation. 

 Around the Wash it disappears beneath the alluvial flats of the Bedford level, but 

 everywhere else it dips below the chalk, which forms so prominent a feature in 

 the physical geography of South-eastern England. 



The chalk, like the oolitic limestone, generally presents a bold escarpment 

 towards the west. It is most extensively developed on the plain of Salisbury. 

 From this, as a centre, the ranges of chalk diverge in different directions. The 

 South Downs stretch along the coast of the Channel as far as Beachy 

 Head. The North Downs bound the valley of the Thames on the south, and 

 terminate in the clififs of Dover. A third range extends to the north-eastward, 

 forming the Marlborough Downs, the Chiltern Hills, and the East Anglian 

 Heights, which terminate with Hunstanton Cliff, at the mouth of the Wash, but 

 once again rise to the north of that shallow bay in the wolds of Lincoln and 

 York. 



Clays, sands, limestones, and crag of the tertiary age overlie the chalk in the so- 

 called basins of London and Hampshire ; but between the North and South Downs 

 the chalk has been removed by denudation, and the subjacent strata which occupy 

 the district known as the Weald have been laid bare. Bounded by escarpments of 



* Culminating summits of mountain groups of Great Britain : — 



Northern Highlands, Ben Wyvis 3,422 feet. 



Grampians, Ben Nevis 4,406 „ 



„ Ben Muich (Mac) Dhui 4,296 „ 



Hflls of South Scotland, Merrick 2,764 „ 



„ „ Cheviot 2,669 „ 



Pennine Chain, Cross Fell 2,928 „ 



Cambrian mountains, Sea Fell 3,230 „ 



Welsh mountains, Snowdon 3,590 „ 



Moimtains of Devonshire and Cornwall, Yes Tor (Dartmoor) . . , 2,077 „ 



