THe Biack WaTER OF DEE. 189 
distinct types of scenery in accordance with the two different 
types of rock upon which it has been imposed :— 
1. The Dornell and Laurieston plains resting upon the 
softer greywackes and shales. 
2. The Gelston scenery imposed upon the highly resistant 
plutonics. 
In the first case—that of the greywackes—very little of the 
original plain is left. On the eastern bank of the valley the 
highest points are the Livingstone and Dornell Hills, none of 
them quite 600 feet, while on the western side the Devil’s 
Dike at Barstobrick is only 525 feet. Between these heights 
lie the Kirkconnel Moor and the Beoch Moor, the Woodhall 
Loch, the Glentoo and Bargatton Lochs. The moors and 
lochs have an average altitude of about 250 feet O.D., so 
that the scenery is mild and the relief of the Dornell Hills is 
not pronounced. 
The second type of scenery in the Gelston area, is of a 
more impressive character. The denudation has been slight, 
and the plain effects are very pronounced. 
On the western bank the valley wall rises up at an acute 
angle to the 1000 foot plain, now stretching along the tops of 
Screel Hill, Bengairn Hill, and Bengour. On the eastern 
bank the valley wall rises with the same steep gradient, but 
only reaches the 650 foot level. 
This latter level, the Gelston Plain, extends eastwards, 
and embraces other two rivers, the Ken and the Urr. Beyond 
the Urr it rises to the tooo foot level. Maidenpap (1000) and 
Cuil Hill (1350) mark the continuance of the 1000 foot plain. 
The 1000 foot plain has been denuded down to a 650 foot 
plain over a width of seven miles, and this vast erosion has 
been accomplished by three streams. They must have been 
forced to accomplish lateral erosion by some barrier further 
to the south-westwards, a barrier which we find in the 
volcanic rocks of the Lake District. 
The later work of this stream, the Black Dee, its other 
plains and captures, will be dealt with in a further communi- 
cation. 
