Ae Fee Ree Te 
1878. ] The Origin and Formation of Prairies. 301 
And first, is it true that trees will not, as a general thing, grow 
in swamps, or in ground that has once been a stagnant marsh ? 
That there are but few species of trees that will grow in swamps 
covered with stagnant water none perhaps will deny; but that 
these same swamps will not, after they have been drained and 
dried, allow the growth of arborescent vegetation remains to be 
proved. All of Prof. Lesquereux’s arguments and citations of 
authorities in reply to Prof. Winchell’s objections to the theory of 
excessive moisture, cover but this one point, viz., that trees will 
not grow on lands saturated with stagnant water, and leave un- 
proved the other and most important statement that they will not 
grow there when the ground has become dry. Should this state- 
ment be true, we ought to find extensive prairies in many regions 
where prairies are rare; for instance, along our low Atlantic coast, 
and the delta of the Mississippi River. Especially ought we to 
expect to find such tracts along the Amazon, instead of finding 
there the densest forests on the globe. 
Long ago, in the American Journal of Science, Prof. Dana, in 
writing on the origin of prairies, gave the results of his own ob- 
servations made in the Mohawk valley, and cited observations 
made by Prof. Verrill in Maine and Labrador. In this article it 
is stated that in Maine'the bottoms of the lakes are, near the 
shores, composed of black, soft, vegetable mud of great depth; 
and though sedges and rushes are found growing at the water's 
edge, various kinds of trees approach very near the shore, grow- 
ing even where the supporting soil is soft and wet. In cases 
where lakes and bogs have been drained, although grasses and 
sedges may get the mastery the first year or two, forest trees 
afterward gain the ascendency and keep it. In Labrador, trees 
were found growing in peat bogs, in the very borders of lakes 
and pools of stagnant waters. If trees will grow in stagnant 
marshes and on peat bogs in Maine and Labrador and are not 
found growing in similar situations in the Mississippi Valley, some 
other explanation of the fact must be sought than the chemical 
nature or the fineness of the soil. 
But I believe that even in the Mississippi Valley we shall have 
no difficulty in finding luxuriant forests in situations where, ac- 
cording to Prof. Lesquereux, we ought to find only prairies; 
nor difficulty in finding prairies where we should be led to expect 
to find abundant timber. The soil of the Mississippi flood-plain 
has been deposited as in the case of other large’rivers. In some =~ 
