1905] Harper,— Coastal Plain Plants in New England 77 
an area of at least 10,000 square miles where most of these aquatics 
are wanting for a similar reason.) 
For the distribution of the other plants under consideration the 
explanation is probably to be found in the nature of the soil. It 
happens that almost the whole surface of the coastal plain is covered 
with unconsolidated sedimentary deposits (principally the Lafay- 
ette and Columbia formations) which are of about the same age as 
the glacial drift and resemble it to a considerable extent in chemical 
and physical composition. The Columbia in particular, the newest 
and uppermost, is often (perhaps usually) composed of almost pure 
sand, scarcely distinguishable from the more sandy phases of the 
drift. Streams rising in that part of the country covered by Pleis- 
tocene sands (whether Columbia or glacial) are rarely or never 
muddy but usually discolored with vegetable matter, while in the 
Piedmont region clay soil and muddy streams predominate (giving 
rise to the impression common among some people who have traveled 
a little that all Southern rivers are muddy). 
The plants under discussion all grow on these well washed Pleis- 
tocene sands or in peaty deposits overlying them, all of which are 
very deficient in available plant food. Peat-bogs are not confined to 
cool climates as some may suppose (because of their abundance in 
the glaciated regions in which most scientists live, both in North 
America and Europe), but are equally characteristic of the coastal 
plain. Okefinokee Swamp, in the extreme southern part of Georgia, 
with an average annual temperature of about 70° F. (and less rain- 
fall than almost any other part of that state), is mainly a vast peat- 
bog, containing about the same proportions of sphagnum, ferns, 
carnivorous herbs, Ericaceous shrubs and coniferous trees as the 
well known cedar-swamps of New England (and with not a few 
species in common). 
It will be noticed that (taking the Engler & Prantl sequence as 
a criterion) most of the species above mentioned stand rather low in 
the scale (for vascular plants, the lower cryptogams not being con- 
sidered here), also that there are few trees and shrubs among them. 
This is doubtless due to the comparative newness and sterility of the 
soil in which they grow. It is well known that when a soil is first 
thrown open to settlement for plants, as in an area recently emerged 
from the sea or laid bare by glaciers, it is first taken possession of 
by the lowest forms of vegetation, such as algae, lichens and mosses, 
