460 On the Agricultural Geology of England and Wales. 



grit, and coal measures. Near it, on the south-east, are the 

 syenitic outbursts of Charnwood Forest. Further to the south- 

 west are the silurian rocks and associated traps and syenites of the 

 Malverns. The chalk and oolites have been thrown up in parallel 

 ridges, with a strike curving first to the south-east and then to the 

 south-west, and ranging from Flamborougli Head in Yorkshire 

 to the coast of Devon and Dorset. The oolitic ridges are known 

 in Yorkshire as the Hambledon and Howardlan Hills (middle 

 oolite), and the eastern Moors (lower oolite). The prolongation 

 ,of the ridge of the lower oolite to the south-west forms the Cots- 

 wolds of Oxfordshire and Gloucestershire. The chalk range is 

 knov/n as the Wolds of Yorkshire and Lincolnshire, the Downs 

 of Norfolk, the Gogmagog Hills of Cambridge, the Dunstable, 

 Luton, and Warden White Hills of Bedfordshire, the Chilterns 

 of Buckinghamshire, Berkshire, and Oxfordshire, passing into 

 the elevated platform of Salisbury Plain and the Hampshire 

 Hills, and terminating on the coast of Dorsetshire in the steep 

 ridge of Purbeck Hill. The elevation of the chalk from north- 

 east to south-west appears to have been prior to the deposit of 

 the eocene tertiaries and London clay, which are only found on 

 the east of it ; but another, and subsequent line of disturbance, 

 ranging east and west, has thrown up the chalk ranges of the 

 North and South Dovi^ns, exposing the subjacent oolitic strata of 

 the Wealden, in the triangular denudation between them, and 

 separating the once continuous eocene tertiaries into the districts 

 commonly, though erroneousl}^, called basins, of London and 

 Hampshire. 



The position and direction of the chains of hills have influenced 

 the lines of the rivers; they have also influenced the distribution 

 of the erratic tertiaries. These, however, are quite independent 

 of the rivers. They are far above the influence of existing streams, 

 which, so far from having formed them, have in many cases cut 

 deep channels through them. 



Marine origin of the erratic deposits on submerged land. — The 

 marine origin of the erratic deposits is proved by the marine shells 

 locally distributed through them at many points and over wide 

 areas. From the large percentage of shells of existing species 

 which these deposits contain, they are proved to belong to that 

 portion of the tertiary series which, in the classification of Lyell, 

 is called the pleistocene, or newer pliocene. The same fact is 

 proved by their superposition in Norfolk to the mammalian crag, 

 or older pliocene. England is proved to have been dry land, 

 inhabited by the elephant, rhinoceros, hippopotamus, and other 

 large mammals, before its submergence beneath the sea of this 

 epoch ; by the Ibrest at Cromer and Happisburgh, buried beneath 

 more than three hundred feet of these erratic tertiaries, and 



