314 TTNEDAXE ESCAEPMEJTTS ' 



the materials denuded within the river-basin. It would be im- 

 possible to decide, from their mere breadth, which represent the 

 longitudinal limbs of the H or A, and which are the main trans- 

 verse entrances upon them. But what is the relation of the out- 

 crops represented by the cross-bar ? 



2. Transverse Valleys. — In the lower third of l^orth Tynedale 

 the outcrops stretch* across the valley in the form of a bent bow 

 pointing down the river. It would be difficult to find a better 

 illustration of longitudinal and transverse than is here supplied. 

 Observe first the condition of the outcrops in crossing the valley. 

 From a good vantage point, such as the great bank south of 

 Chollerton, the valley seems divided into compartments by broad 

 bars pointing across from each side. In such a view the eye is 

 misled as to details, but it is guided aright to the great fact that 

 the denudation which carved out the valley-system, in leaving 

 these spit-like ridges, has worked along the lines of the internal 

 structure. In reality they are never quite vis-a-vis; the safest 

 generalization to make is that they represent only the high 

 grounds between wide-mouthed transverse tributaries, but they 

 combine to give the valley the general aspect, as intelligent eyes 

 have not failed to remark, of a succession of lake-basins strung 

 upon a long winding hollow. 



Following one of these broad ridges away from the valley it 

 continues to be clearly manifested that the results of denudation 

 have more or less opened out the lines of structure. The ridge 

 is at once recognised as compounded of many various outcrops, 

 which, as the streams lessen, and the transverse valley becomes 

 lost in the rolling plateau within, become more individualized, 

 each after its kind, and here and there rise in scars and crags. 

 At length the watershed is reached, and so far fi'om the ridges 

 having disappeared, they generally crest it boldly; as notably 

 happens about Sewingshields, on the west, and in the grand 

 crags about the source of the Wansbeck. 



The ridges pass over beyond Sewingshields in a dii^ection verg- 

 ing towards parallelism with the lower half of the South Tyne, 



* The geological term strike applied to the general direction of outcrops is just this 

 word In another form. German streichen. 



