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scape. Limestone usually weathers into broad uplands where 

 solitude reigns on often absolutely treeless heights. The 

 characteristics of the chalk are somewhat similar. Trees are not 

 common, but the solitude of such heights is materially assisted by 

 the velvety grass which covers the scanty layer of soil. The 

 larger valleys are practically waterless, and everywhere show 

 flecks of dry white rubble through the thin coating of soil. 



A view over the broad plams gives little suggestion of hollows 

 or gorges, and in travelling the country we do not become aware 

 of them until we stand upon the very brink of their steep slopes. 



Peculiarly enough, although the valleys are waterless, they 

 show evident signs of water action. Streamlets on limestone 

 moors not infrequently suddenly disappear into " swallow holes " 

 and continue their courses underground through crevices, joints 

 and caves of which the limestone is full, to emerge again into open 

 day and continue their courses to the sea. The regions of Cheddar 

 and the Pennines contain numerous examples of these, and good 

 -examples are to be found in Belgium in the River Styx and the 

 River Lesse, the details of whose underground courses even to-day 

 are not fully ascertained. 



Quarries form a well-marked feature in limestone scenery. 

 The stone is worked both for building and for road ballast. The 

 work of building many of our finest cathedrals was facilitated 

 ;by the supply of stone from limestone regions. Purbeck furnishes 

 two or three varieties of excellent stone in the shape of its marbles, 

 which are highly prized for decorative architectural work. Chalk 

 hills or, as they are more familiarly termed, " downs," weather 

 much in the same way as limestone, but being softer and more 

 pulverulent, usually take the form of smooth rolling hills. The 

 nature of the country and the regularity of the various gradients, 

 no matter from which side the down is approached, is well brought 

 out by reference to an orographical map. Limestone and chalk 

 are then brought markedly in contrast by the form taken by their 

 -contours. Three suitable regions might be taken as typical: — 

 (i.) The area of the Downs, which is distinctly soft chalk; (ii.), 

 the Mendips or Mid Pennines, as illustrative of mountain lime- 

 stone; and (iii.) the South Western portion of the Southern 

 Uplands, which are typical of volcanic regions. Taken in succes- 

 sion the map shows a marked increase in the tendency to 

 irregularity of the contours. In the Downs the almost parallel 

 nature of the contours is clearly characteristic, whilst in proceeding 

 from limestone to volcanic areas the irregularity is again markedly 

 increased. William Smith, the Father of English Geology, says: 

 "I could see that the Wolds contained chalk by their contour. " 



Caves are of common occurrence in calcium areas, and many 

 of these give rise to rivers. As a rule, however, the water supply 

 is distinctly intermittent and the outlet usually in the shape of a 

 svphon. As the sea cuts away the front of the cliff these are 

 often left exposed to the action of its waters and become the 



