THE Lower NITH. 129 
has both the age and the volume necessary to produce a large 
and deep valley, but unfortunately it is harassed with burdens 
unexplained and mysterious. Its floods are famous, and its 
record in this respect is as bad as the long, tortuous streams 
crawling towards the east coast. In navigation there is no 
comparison between it and the larger rivers, Clyde or Mersey, 
while much smaller streams, like the Annan and the Urr, 
outrival it. Navigation is now only practicable to Kingholm 
Quay, six miles upstream; and a hurried discharge is impera- 
tive in order to escape a fortnight’s delay for full tides. Boats 
entering the county town are only a memory of the last 
generation. 
DuMFRIES BasIN. 
This ancient basin of New Red Sandstones stretches from 
the Solway north to Auldgirth. It is of horse-shoe shape, 
with steep valley walls on the western side. It embraces the 
whole central valley of Lower Nithsdale and the desolate 
valley of Lochar Moss on the east, and that of the Crook’s 
Pow on the west. The Red Sandstones of this basin are 
intercalated with bands of hard breccia. Gradually the softer 
sandstones have been removed, leaving the breccia to weather 
out in the form of prominent ridges, such as the Craigs, 
Chapelhill, Carruchan, and Goldielea. The intervening 
hollows are now occupied by the Nith, the Crook’s Pow, and 
the Cargen Pow. The central stream traverses at least three 
distinct types of valley formation in its course from Auldgirth 
through the burghs to the Solway. 
1. As it traverses the parishes of Kirkmahoe and Holy- 
wood it meanders gently through a wide fertile plain of low 
gradient. 
2. At the Castledykes bend, south of Dumfries, both 
valley and central flood plain are absent. The river is here 
entrenched—presenting an entirely new aspect. 
3. At Glencaple the valley is V-shaped, with steep sides 
and a flat floor. 
NitH oF THREE DIFFERENT AGES. 
If we assume that the deep gorge at Blackwood is a true 
