PRAIRIE (ante), the French word to signify meadows, and qualified by them in use by distinguishing natural prairie from artificial prairie or meadow. From the vastness of the Amerieau prairie, so named by the early French discoverers, it has beau erroneously inferred that the name implied great extent of natural meadow. Small prairies are found in the primeval state in nearly every part of the world, and oases of prairie are not infrequent in the midst of the forest lands of the middle states. Prairies of vast extent are also found far above the altitude of 1500 ft. as given in the above article. The great plateaus of Wyoming, Montana, Colorado, and New Mexico, are prairies of a less fertile character, fresher from nature's great processits of erosion, and having too little rainfall to make a rank vegetation. They lie from 2,000 to 7,000 ft. above the sea. Narrow valleys near the sources of the great tributaries of the Mississippi furnish excellent sum flier pasturage to the height of 10,000 feet. On the line of the Union Pacific railway, mowing machines are used to cut the natural hay in some of these valleys 6,000 ft. above the sea. The prairie called Laramie plains is between 6,000 and 7,000 ft. above the sea. Marsh meadows by the sea side are equally prairies in the original meaning of the word. The origin of the very fertile prairies in the valley of the Mississippi river proper, now mostly under culture, has been the subject of many theories.' Row soil so rich, upon which most of the trees of the neighboring forests flourish luxuriantly when pro tected, should have failed to be covered with them in a state of nature is the question. It is answered by vegetable physiologists thus: The excrements of vegetable growths from the roots of trees and plants, and even the annual accumulation of their own leaves after a continuous growth of the same species, become poisonous to the genera which emit them, though perfectly nutritious to plants of different families. It is claimed that the long con tinuance of forest growth on a rich soil, made constantly richer by its own annual deposits of leaves, dead wood, and excretions from the roots, finally makes it unfit for their growth. Sickliness and decay produce more and more dead wood, so that fires finally de stroy utterly what the soil to nourish. Rank weeds and grasses follow, which in their turn, ripe and dry in autumn, make food for new flames that destroy the remnant of tree vegetation, even the young brood of new species which might otherwise hold their ground. Tree-roots cannot long live when their tops are destroyed. Perennials on the
other hand have an extraordinary power to preserve life in their roots, under the action of prairie fires. Once in full possession of the soil, it is easy to see that annual autumn fires where there are 'not animals enough to feed clown the summer growth, will not only preserve the ground won from the forest by grasses, but will singe the surrounding forests, and wherever they are sickly from the cause first named, will finally consume them. Ages of continuous growth of grasses and other perennials, and of countless annuals, have assimilated those qualities in the soil that became noxious to trees; and in nature's rotation of crops the soil has again become fitted for their growth. It is only necessary to check the annual prairie fires for a new crop of forests to dominate the grasses. Trees were beginning to resume possession of-tile prairies when settlements began. The increase of the buffalo decreased the food for autumn fires by so much as they pastured upon the grasses. The moisture of the ground contiguous to streams and the sweetness of the late summer grasses in these places would naturally make spots where trees could have time to get rooted in the absence of fires. Profs. Hall, and Whitney ascribe the treeless condition of the prairies to the finely comminuted condition of soils formed out of a sedimentary rock strata, but this theory is entirely unsatisfactory and inconclusive., Dr. Lesquereux, in his geological report for Illinois, supposes that the prairies have all been lake beds, first occupied by aquatic plants, succeeded as they became drier by grasses, the burning of which prevented the rooting of trees. Prof. Winchell claims that the vegetation of the prairies was pre-glacial, that on the subsidence of the glacial drift the seed took and held possession of the soil, etc. Prof. J. S. New berry suggests a theory of climatic influences as to rainfall, etc.. but presents no facts to explain why n.w. Ohio was a dense forest, and in the same latitude, with the same cli mate, and rainfall, n. Illinois was nearly all prairie. Unquestionably forests require more rainfall and are more likely to be killed out by a repetition of severe droughts than the grasses, but no such differences occur to show cause for the diverse conditions just cited.
Prairies of great extent are found in the southern part of South America, e. of the Andes, similar in character to those of the western states; less fertile than those of the anfley of the upper Mississippi, and less subject to extremes of cold than the the table land prairies of the United States.