336 Expedition to the 



off gradually by evaporation, which renders the atmosphere 

 humid and unhealthy. The vegetable mould of which the 

 immediate surface is composed, and the abundance of vege- 

 tables that spring and decay upon the ground, contribute 

 largely to render these exhalations more deleterious- Al- 

 though there are but few swamps or mashes, and very rarely 

 pools of stagnant water to be met with in this region, still, 

 the general water-table of the country is so little inclined, 

 that the streams, having but a moderate descent, are uni- 

 formly sluggish, often exhibiting the appearance of a suc- 

 cession of stagnant pools. The consequence is, that the ve- 

 getable matter they contain, instead of being carried away by 

 the strength of the current, is deposited upon the bottoms and 

 sides of the channels, and while in its purtrescent state, 

 serves to augment the quantity of noxious effluvia with which 

 the atmosphere is charged. 



The population of this region, compared with its extent, 

 is very limited; and, with the exception of a few villages, the 

 settlements are very scattering. Large portions of it, em- 

 bracing the northerly parts of Indiana and Ilhnois, are al- 

 most entirely destitute of inhabitants. Many parts of the 

 country must remain uninhabited for many years to come, 

 on account of the scarcity of timber, and other deficiencies, 

 such as the want of mill-seats, springs of water, &c., which 

 are serious blemishes in the character of a large proportion 

 of the country. There are however, numerous and exten- 

 sive tracts within this region, possessed of a rich soil, and in 

 other respects well adapted for settlements, and presenting 

 the strongest inducements for emigrants to occupy them. 



3. The country of the third order, agreeably to the subdi- 

 vision above given, viz. the valley country, is situated upon 

 the rivers, and is included within the hilly and plain coun- 

 tries above described. The tracts belonging to this order, 

 usually denominated bottoms, are altogether alluvial, being 

 composed of alternate layers of sand and soil, deposited from 

 the water of the rivers upon which they are respectively si- 

 tuated. The alluvion thus deposited, having once constitut- 

 ed a part of the surface of the countries drained by the water 

 courses tributary to the rivers along which the deposit has 

 been made, it will readily be inferred that the fecundity of 

 the vallies will, in some measure, correspond with that of 

 the countries whence their alluvion was derived. According- 

 ly, we find the bottoms more or less productive, in propor- 

 tion to the fertility of the regions in which the rivers take 



