30 GEOLOGY OF ILLINOIS. 



and tbe iron nodules are abundant along the river bank, where they 

 have been washed out of the easily decomposed shale. 



Sand, Gravel and Clay. — The materials for brick are abundant almost 

 everywhere, and can be had wherever wanted. Good brick clay can be 

 found in the subsoil of the uplands, and sand is found both in the loess 

 deposits of the river bluffs and in the beds of the streams. The second 

 bottom or terrace land along the Wabash river affords an abundance of 

 gravel for road ballast, n.aking cements, etc. 



Soil and Timber. — From Hutsonville south, there is a belt of alluvial 

 bottom and terrace laud, from one to three miles in width, extending to 

 the mouth of Lamotte creek, a distance of about ten miles. This is 

 mostly prairie, and the soil is a deep, sandy loam, and very productive. 

 The upland prairies have a chocolate-colored soil not so rich iu humus 

 as the black prairie soils of Central Illinois, but yielding fair crops of 

 corn, wheat, oats, clover, etc. On the timbered lands the soil is some- 

 what variable. Where the surface is broken the soil is thin, but on the 

 more level portions, where tbe growth is composed in part of black 

 walnut, sugar tree, linden, hackberry and wild cherry, the soil is very 

 productive, and yields annually large crops of all the cereals usually 

 grown in this latitude. The varieties of timber observed in this county 

 were the common species of oak aud hickory, black and white walnut, 

 white and sugar maple, slippery and red elm, honey locust, linden, 

 hackberry, ash, red birch, cotton wood, sycamore, coffee nut, black gum, 

 pecan, persimmon, paw-paw, red thorn, crab apple, wild plum, sassafras, 

 red bud, dog-wood, iron-wood, etc. 



Indian Mounds. — One mile south of Hutsonville, on the gravel terrace, 

 and about 200 yards from the river bank, there is a curious group of 

 mounds, 55 in number, and from eight to ten feet in hight. One of the 

 largest mounds is surrounded by a wall of earth raised about three feet 

 above the surface, and from five to six feet in width, inclosing a space 

 of ground about a hundred feet in diameter. This was undoubtedly 

 the site of an ancient village belonging to that mysterious people whom 

 we call the "Mound builders," for the want of some more distinctive 

 appellation, and who once, and probably for a long series of years 

 inhabited the valleys of the Mississippi and its tributaries, as is proven 

 by their earth works scattered over the whole area of the western and 

 southern States. But little is at present known of the character and 

 habits of this ancient people, whence they came or whither they went, 

 and the study of these ancient works, and the ornaments and implements 

 belonging to those who built them, is perhaps the only available clue 

 to their history. 



