CHARACTER OF THE SOIL. 81 



In the course of ages a soil somewhat resembling an ash-heap 

 must have been thus gradually created, and it is no wonder 

 that it should be declared to be inexhaustible in fertility. In 

 Europe such tracts of fertile country as the plain of Lombardy 

 are known to have yielded crops for more than 2000 years 

 without intermission, and yet no one says that the soil is ex- 

 hausted. Here we have a tract naturally as rich, and with 

 the addition of its own crops rotting upon its surface, and 

 adding to its stores of fertility, all that time. It need occa- 

 sion no surprise therefore to be told of twenty or thirty crops 

 of Indian corn being taken in succession from the same land, 

 without manure, every crop, good or better, according to the 

 nature of the season. 



Externally the prairie soil appears to be a rich black 

 mould with sufficient sand to render it friable, the surface 

 varying in depth from twelve inches to several feet, lying on a 

 rich but not stiff yellow subsoil, below which there is generally 

 blue clay. This drift surface lies on rocks consisting of shales, 

 sandstones, and limestones, belonging to the coal measures. 



Its chemical composition has been ascertained for me by 

 Professor Voelcker, consulting chemist to the Koyal Agricul- 

 tural Society of England, to whom I sent four samples of 

 prairie soil for analysis, brought by me from different and dis- 

 tant points of the lands belonging to the Illinois Central Kail- 

 way Company. The letter of Professor Voelcker, and a copy 

 of the complete analysis, will be found in an Appendix. They 

 bear out completely the high character for fertility which prac- 

 tice and experience had already proved these soils to possess. 

 The most noticeable feature in the analysis, as it appears to 

 me, is the very large quantity of nitrogen which each of the 

 soils contains, nearly twice as much as the most fertile soils 

 of Britain. In each case, taking the soil at an average depth 

 of ten inches, an acre of these prairies will contain upwards 

 4* 



