It is well known that in the richest and most dry and level tracts, the aboriginal inhabitants, before they had the use of fire-arms, were in the habit of enclosing their game in circular fires in order that it might bewilder and frighten the animals, and thus render them an easy prey.
From whatever cause the prairies at first originated, they are undoubt edly perpetuated by the autumnal fires that have annually swept over them from an era probably long anterior to the earliest records of history. Along the streams and in other places where vegetation does not suffer from the drought, the fire does not encroach much; consequently the forests prevail there, and probably increase in some places upon the prairies. As soon as the prairies are plowed and the heavy grass kept under, young timber begins to sprout, particularly such as is produced by winged seeds, as cottonwood, sycamore, etc.
When the tough sward of the prairie is once formed, timber will not easily take root. Destroy the prairie turf by the plow or by any other method and it is soon converted into forest land. There are large tracts of country in the older settlements where, a number of years ago, the farmers mowed their hay, and these tracts are now covered with a forest of young timber of rapid growth.
As soon as timber or orchards are planted in the prairies, they grow with unexampled luxuriance. A correspondent writes from Adams County that "locust trees, planted, or rather sown, on prairie land near Quincy, attained in four years a height of 25 feet and their trunks a diameter of from 4 to 5 inches. These grew in close, crowded rows, affording a dense and arbory shade. In a few instances where the same kind of trees had been planted out in a more open manner, they grew in the same period to a thickness of 6 inches, and in from seven to ten years from their planting, have been known to attain sufficient bulk to make posts and rails.
From May to October, the prairies are covered with tall grass and flower-producing weeds. In June and July, they seem like an ocean of flowers of various hues, waving to the breezes which sweep over them. The numerous tall flowering shrubs which grow luxuriantly over these plains present a striking and delightful appearance. The bushes are often over
topped with the common hop.
In the prairie region there are numerous ponds; some are formed from the surface water, the effect of rain and the melting of snows in the spring, and others near the rivers from their overflowing.
In the southern part of the state, the prairies are comparatively small, varying in size from those of several miles in extent to those which contain only a few acres. As we go northward, they widen and extend on the more elevated ground between the watercourses to a vast distance, and are frequently from six to twelve miles in width. Their borders are by no means uniform, but are intersected in every direction by strips of forest land advancing into and receding from the prairie towards the watercourses whose banks are always lined with timber, principally of luxuriant growth. Between these streams, in many instances, are copses and groves of timber containing from 100 to 2,000 acres in the midst of the prairies like islands in the ocean.
The largest tract of prairie in Illinois is denominated the Grand Prairie. Under this general name is embraced the country lying between the waters which fall into the Mississippi and those which enter the Wabash rivers. It does not consist of one vast tract, boundless to the vision, and uninhabit able for want of timber, but is made up of continuous tracts with points of timber projecting inward and long arms of prairie extending between the creeks and smaller streams.
The southern points of the Grand Prairie are formed in the northeastern parts of Jackson County. Grand Prairie then extends in a northeastern course between the streams, varying in width from 1 to 10 or 12 miles, through Perry, Washington, Jefferson, Marion, Fayette, Effingham, and Coles into Champaign and Iroquois counties where it becomes connected with the prairies that project eastward from the Illinois River and its tributaries. A large *am lies in Marion County between the waters of Crooked Creek and the east fork of the Kaskaskia River.