1995] LIVINGSTON—RELATION OF SOILS TO VEGETATION 23 
area. ‘These ridges are moraines and between them are lower and 
more level stretches consisting for the most part of plains which slope 
downward from the ridge margin to the nearest stream. The sur- 
face soil of these plains is almost pure sand in many instances, while 
in others it contains enough more finely divided material to be termed 
loamy sand. Gravel deposits are very rare and it is seldom that one 
finds in the plains even scattering pebbles. The moraines are more 
heterogeneous in composition, containing clay, loam, and _ gravel 
as well as sand. An accurate description of these features is to be 
found in the geological report referred to, and will be here omitted. 
(See map.) 
The soils are nearly all sandy, the only exception to this state- 
ment being a few low clay areas and certain clayey portions of the 
larger moraines. The surface soil of most of the ridges is gravelly 
and loamy sand, the predominating sand containing a sufficient 
admixture of finer particles to produce a marked difference in physical 
properties from that of the true sand plains, while they also contain 
pebbles and sometimes scattered bowlders. The slopes downward 
from these ridges are of sand, either pure or loamy, seldom containing 
many pebbles of any considerable size. The true sand plains, 
which lie at the bottom of some of the valleys, contain little or no 
loamy material and no pebbles. Their surface is a fine grayish-white 
sand, which drifts readily by the. wind when loosened. Obviously 
difference in degree of water-washing determines these different soil 
characters. 
3 Sandy soils are composed of coarse particles and contain much 
| silica, loamy soils are of finer particles and contain considerable 
quantities of alumina, while clay soils are of still more finely divided 
materials and contain a much larger percentage of alumina. Since 
all of this material was transported from the north by the glacial 
| ice, and since it must have been quite thoroughly mixed by this 
| agency, it is reasonable to suppose that, had it not been washed by 
water during and after its deposit, it would be at least fairly uniform 
in its mineral constituents. The washing process sorted the soils 
according to size of particles, but also according to their chemical 
nature. This is partly due to the fact that alumina breaks down 
into fine particles more readily than does silica. It is also due to the 
