10 PRINCIPAL FEATURES 



which terminate the ' tabular hills ' of the districts of Scar- 

 borough and Castle Howard. These hills range east and west, 

 and are escarped to the north across the many branches of the 

 Derwent from Scarborough to Bilsdale ; but run south-east from 

 Coxwold to Malton, with escarpments to the south-west. Simi- 

 larly in the West Riding of Yorkshire, we trace many such 

 lines of escarpment which terminate sloping terraces of sand- 

 stone ; the sandstone resting on more easily disintegrated shales. 

 Thus have the long cliffs of our Wolds and our Hambletons 

 been formed : thus has a remarkable feature of the physical 

 geography of England been produced the almost uninterrupted 

 range of our chalk hills from. Flamborough to Dorsetshire and 

 Kent, and the many parallel ranges of the oolites which traverse 

 the middle of the island. The simple principle which so fully 

 explains it the unequal action of water upon a basis of un- 

 equally resisting materials is applicable to almost every indi- 

 vidual hill in Yorkshire, and is equally successful when we 

 inquire into the effect of rivers in causing or modifying the 

 cascades which enliven their course. 



The features of individual hills and valleys depend mainly on 

 the materials of which they consist, and on the manner in which 

 they are arranged. As an example, we may take the outline of 

 Ingleborough toward the west. The prominent parts of the 

 outline are due to the hard millstone grit (m) which crowns the 

 mountain ; to the hard limestone (/), and the hard sandstone (s) 

 which jut out on the side; the steep slope below is formed 

 chiefly of perishing shales, and the broad base which supports 

 the conical mass is a floor of solid limestone. Penygheut, Whern- 

 side, Bear's Head, Stag's Fell, Pen Hill, and many other of the 

 most conspicuous hills in the north-west of Yorkshire, exhibit 

 similar outlines due to similar alternations of strata. 



In strong contrast with these are the forms in Hougill Fells, 

 which, composed of slaty rocks placed at high angles of inclina- 

 tion, shoot up in pyramidal ridges and obtusely angular summits, 

 like many hills composed of the same rocks in Westmoreland. 



