ELISHA MITCHELL SCIENTIFIC SOCIETY 112 
fluenced by the slope of the surface, the depth and poros- 
ity of the soil, and the character of the underlying rock. 
In connection with this study of the geologic conditions 
influencing the possibilities of waterpower development, 
it should be noted that the occurrence of lakes, swamps 
or marshes and poorly-drained level areas, deep and 
porous soils, such as the sandy and gravelly soils from 
10 to 100 feet deep, which occur in the larger part of the 
Piedmont plateau and mountain regions of the Carolinas, 
the great sand hills of the southern coastal plain region, 
and the porous sands and gravels of the glaciated regions 
of the Northern states, all facilitate the uniformity of 
the flow of the streams in these several regions; and in 
some regions the jointed, fissured and crushed condition 
of the underlying rock exerts a favorable influence in the 
same direction. 
NOTES ON GRASSES. 
1) CONTRIBUTIONS FROM MY HERBARIUM. NO. Iv. 
WwW. W. ASHE. 
Since the publication of a paper on the Dichotomous 
Group of Panicum in the Eastern United States (in this 
Journal, vol. xv, Nov., 1898) I have found among some 
duplicates additional material of a plant, a single speci- 
men of which [ had at that. time, but such scanty mate- 
rial that I did not care to base a species on it, though it 
1) Issued April 20, 1899. 
