ELISHA MITCHELL SCIENTIFIC SOCIETY 94 
this phenomenon is to be found in the fact that the 
deep, porous sands of the region serve as a sponge in 
soaking up the rains as they fall, turning loose this 
water gradually during the dry season through numer- 
ous springs. 
In the case of many others of the small powers in 
this region, as that on Colly creek in Bladen county 
and others in the different eastern counties, the uni- 
formity of the flow throughout the year is favored by 
the further condition that the tributaries of these 
streams pass through extensive swamp areas which also 
serve to store the water for use during dry weather. 
WATERPOWERS IN THE FALL LINE ZONE. 
Along the ‘‘fall line’’ or the fall line zone in North 
Carolina there are conditions favorable for the de- 
velopment of waterpowersof considerable magnitude on 
our larger streams. And since the exact position of this 
fall line is not clearly defined, and as the conditions favor- 
ing waterpower development extend across a considerable 
belt or zone where this lineis crossed by the larger 
streams, itis better in this connection te consider together 
these conditions asthey exist at and for a few miles on 
both sides of this boundary line between the coastal plain 
and Piedmont plateau regions. 
ON THE ROANOKE RIVER. 
The conditions favoring waterpower development on 
the Roanoke river in this zone, which at this point has a 
width of about 9 miles, extending up the river from Wel- 
don, may be considered as typical of those existing other 
points. Waterpower developments of considerable mag- 
nitude are now in progress on the Roanoke and are being 
planned on the Cape Fear and Yadkin. 
