334 



Yorkshire Hills. 



their minor escarpments facing west, the 

 railway emerges, after crossing the Trent, 

 on a second plain, through which, swelled 

 by many tributaries the Idle, the Don, 

 the Calder, the Aire, the Wharfe, the 

 Nidd, the Ure, the Swale, and the Der- 

 went the Trent and the Ouse flow to 

 enter the famous estuary of the Humber. 

 Passing north by York the same plain 

 forms the bottom of the low broad valley 

 that lies between the westward rising 

 dip-slopes of the Millstone Grit, &c., and 

 the bold escarpment of the Yorkshire 

 Oolites on the east, till at length it passes 

 out to sea on either side of the estuary of 

 the Tees. The adjoining diagram repre- 

 sents the general structure of the region 

 on a line from Ingleborough on the west 

 to the Oolitic moors. 



On the west lie the outlying heights of 

 the ancient camp of Ingleborough, and of 

 Penyghent, capped with Millstone Grit 

 and Yoredale rocks (2), which, intersected 

 by valleys, gradually dip eastward, the 

 average slope of the ground over long 

 areas often corresponding with the dip of 

 the strata in the manner shown in the 

 diagram, 1 till they slip under the low 

 escarpment of Magnesian Limestone (3). 

 Let the reader attentively consider 

 this part of the diagram, and he may I 

 hope convince himself how little ordinary 

 valleys, large or small, are directly pro- 

 1 This kind of slope is often called a dip-slope. 



