jo AB) JOURNAL OF THE 
a southwesterly or a northeasterly direction along the 
line of the strike of the rocks and thus develop the con- 
ditions favorable for waterpower, mainly where they 
vary their courses and cross from rock of one character 
to one of a different character. In the extreme northern 
portion of the region the tributaries of New river rise 
both on the western slopes of the Blue Ridge and the 
eastern slopes of the Iron mountains, and flow ina general 
northeasterly or northeriy direction, sometimes following 
the line of the strike, and sometimes crossing the latter 
at sharp angles. Along New river and its tributaries 
are a number of shoals which can be developed into valu- 
able waterpowers, occuring mainly at points where the. 
streams cross the strike of the gneissic rock of the region. 
In connection with the development of these water- 
powers, the river gorges are so narrow and the streams 
so rapid that while the construction of large dams is a 
matter attended with no insurmountable difficulties, yet it 
is often difficult to find suitable space for buildings, and 
it has been found more advisable in a number of cases to 
construct small dams and to convey the water from these 
in open ditches or flumes along the banks of the stream 
to suitable points where the power may be utilized. The 
chief difficulty which is met in storing water on these 
streams is that the ponds or storage reservoirs become 
rapidly filled with sand, gravel and bowlders brought 
down in time of flood. Probably the future develop- 
ment of these powers will be largely in connection with 
electrical transmission. 
GEOLOGICAL CONDITIONS AFFECTING THE FLOW OF STREAMS. 
The yearly discharge of a stream depends primarily 
on the amount of rainfall in the region from which the 
stream draws its supply, but in a measure this volume, 
and especially the uniformity of flow, are largely in- 
