i8 9 5. FORMS OF MOUNTAINS. 243 



from descriptions, the straight outline is also a characteristic feature, 

 as we should expect, for there the blocks of rock would be split off 

 along joints as they are in the domains of the frost-king. 



In our own country, though the curve of stream-erosion is the 

 dominant feature, the results of denudation "in the dry way " are 

 easily found, though usually on a small scale. The best illustration 

 is furnished by the terraced hills of the Ingleborough district of 

 Yorkshire, capped with Millstone Grit, beneath which are a few 

 hundred feet of Yoredale rocks, while their bases are composed of 

 Mountain Limestone. The Millstone Grit capping the tops of the 

 highest hills is too porous and too thin to allow important streams to 

 course over its surface, while the drainage of the Limestone region is 

 mainly subterranean. The consequence is that the Millstone Grit 

 and Limestone " scars " have the straight outlines due to the action of 

 frost, which may be well contrasted with the curves of stream- 

 erosion of- the slopes of Yoredale rocks, down which numbers of 

 rills flow. 



Again, in districts where the stratification is not an important 

 factor in determining the outlines of the hills, excellent examples of 

 the work of frost may be seen on a small scale. Many of the cliff- 

 faces of Cambria and Cumbria owe their straight faces to the effects 

 of frost on the joint-planes, and here and there we find a " pocket- 

 edition " of a frost-formed hill, which differs but in size from its more 

 imposing fellows in Alpine regions. From out the hard, regularly- 

 jointed volcanic rocks of the Borrowdale series of Cumbria has been 

 carved the Napes Needle of Great Gable, of which a good illustration 

 is given in Haskett Smith's " Climbing in the British Isles," part i., 

 p. 95. This may well be compared with the Aiguilles of Chamouni 

 as regards form, though its size is insignificant. 



To flowing water, then, we owe the sweeping curves of our 

 beloved hills which, seen afar off on some sunny day, harmonise so 

 well with the quiet grace of a pastoral foreground ; but it is to the 

 frost that those forms are due which appear to most advantage when 

 seen fitfully through the changeful mists — 



" That marvellous array 

 Of temple, palace, citadel, and huge 

 Fantastic pomp of structure without name, 

 In fleecy folds voluminous enwrapp'd." 



J. E. Marr. 



