ORIGIN OF PRAIRIES.
The origin of prairies has occasioned much theory; it is to our mind very simple: they are caused by the Indian custom of annually burning the leaves and grass in autumn, which prevents the growth of any young trees. Time thus will form prairies; for, some of the old trees annually perishing, and there being no undergrowth to supply their place, they become thinner every year; and, as they diminish, they shade the grass less, which therefore grows more luxuriantly; and, where a strong wind carries a fire through dried grass and leaves, which cover the earth with combustible matter several feet deep, the volume of flame destroys all before it; the very animals cannot escape. We have seen it enwrap the forest upon which it was precipitated, and destroy whole acres of trees. After beginning;, the circle widens every year, until the prairies expand boundless as the ocean. Young growth follows the American settlement, since the settler keeps off those annual burnings.
American Quarterly Review.