IV. THYSICAL GEOGRAPHY. 141 



sub-provinces of East and West Humber, by tbe rivers 

 Humber, Ouse, and Wiske. South-east and North-east 

 Yorkshire are tben separated by the political line -which 

 divides the East Riding from the rest of the county ; that 

 portion of the East Riding situate westward of the Ouse 

 being taken as part of the Mid- West vice-county. South- 

 west and Mid-west Yorkshire are separated by the Leeds 

 and Liverpool Canal, and by the river Aire below Leeds. 

 Mid-west and North-ioest Yorkshire are separated by the 

 political boundary between the North and West Ridings ; 

 that boundary being deflected westward so as to pass over 

 Whernside to the south-eastern angle of Westmoreland, 

 in conformity with the water-shed. — Cheviotland is cut off 

 from the more southern part of Northumberland by the 

 river Coquet, and a line continued to Carter Fell from 

 the Linn Bridge. That part of Durham, which is situate 

 between Holy Island and the Tweed, is deemed a portion 

 of Cheviotland. — The large county of Perth is divided 

 into three vice-counties. East Perth is cut off from Mid 

 Perth by the rivers Garry and Tay. Mid Perth is sepa- 

 rated from West Perth by a line traced over the high 

 ground or water-shed so as to divide the tributaries of 

 the Tay from those of the Forth ; the little county of 

 Clackmannan and a small detached portion of Stirling 

 being taken as parts of West Perth. — South and North 

 Aberdeen are separated by lines traced along the water- 

 sheds eastward and westward from Inveriuy. — The great 

 coimty of Inverness is first di%nded by the line of water- 

 shed between the eastern and western sides of Scotland, 

 continued along Loch Erricht to the borders of Perth- 

 shire. The easterly portion, with the addition of Nairn- 

 shire, forms the large vice-county of Easterness. That 

 I)ortion of Inverness, which cuts Elginshire into two dis- 

 joined parts, is deemed to be a portion of this latter 



