9i baker's north YORKSHIRE. 



one or two prominent ' edges ' of gritstone in the tract of the 

 great syncUnal depression of the Carboniferous beds. With 

 these exceptions the surface of the Upper Zone consists entirely 

 of the swells of the highest undulations of the moorlands, 

 sometimes grassy, but more often a combination of heath and 

 turfy swamp. 



The main dales of the west usually terminate at about 400 

 yards, the slope at their upper part from 400 to 550 or 600 

 yards being generally abrupt, but of course the mere water- 

 channels run down from the fell tops. The summit of the Stain- 

 moor Pass is under 500 yards in elevation : that which leads out 

 of the head of Swaledale is a little over 550 yards and that 

 between Arkengarthdale and Gretadale is about 500 yards. At 

 the head of Wensleydale the passes are lower : that which leads 

 into Garsdale is only 350 yards in height : that which leads into 

 the dale of the Eden is a trifle over 400 yards : and that which 

 leads out of Widdale into Dentdale and Ribblesdale is a little 

 under 450 yards. Towards the south they are loftier : the 

 summit of the road to Langstrothdale from Bishopdale is 500 

 yards in elevation and that from Coverdale is nearly 50 yards 

 higher still, whilst between Swaledale and Wensleydale the 

 Buttertubs Pass almost reaches the boundary of the Upper Zone. 

 Of the passes between opposite dales of different drainage 

 systems amongst the eastern moorlands only a few reach the 

 Middle Zone, that between Scugdale and Snilesworth, those 

 which cross the Hambleton plateau and those of the highest 

 part of the ridge of watershed between Esk and Derwent, the 

 rest being all under 300 yards. 



Throughout both the two lower zones cliffs and rocky banks 

 are frequent amongst all the hilly tracts and their slopes and 

 along the line of the sea-coast. Even in the Lower Zone there 

 is a wide extent of uncultivated heatherland both upon the east 

 and west of the central valley ; and of course this is the case 

 to a much greater extent in the Middle Zone. Small tracts of 

 uncultivated heath descend in some places to the lower levels 



