164 GEOLOGY OF ILLINOIS. 



substances were observed at every boring. Silver-shining threads and 

 fibers show themselves in the good peat. They result from the partial 

 decomposition of coarse, wirey grasses. The deposit, and several stages 

 of its growth, seems to have been overflowed by water. At each flood- 

 ing earthy matter and sand was swept over the slough and deposited 

 as a sediment. At present a heavy growth of Spliagnous mosses is 

 flourishing in the greatest profusion over the whole slough. 



This great slough, for the reason stated, is not so valuable for fuel 

 making as the Cat-tail ; but for fertilizing purposes it is perhaps better. 



Many less valuable deposits of peat exist in the low-lands towards the 

 Wiunebago swamps; but I deem a minute description of them unneces- 

 sary at this time. I cannot leave this swampy region, however, without 

 noticing a curious phenomenon often seen among them. I refer to the 

 sand-hills, sand-dunes, sand-blows, or <; blow outs," as they are called 

 in the common speech of the people. The wind has built the sand into 

 curious-shaped, ever-changing hills. The "blow out," about twelve miles 

 south of Sterling, is a circular range of low sand hills, inclosing a small 

 lake. It looks like the extinct crater of some old volcano, but owes its 

 peculiar shape simply to the action of prairie winds. 



The Sphagnus mosses and the highly concentrated cooked vegeta- 

 ble matter of these peat beds, in chemical composition, are similar to the 

 woods of our forest trees. Where pure, ripe, and fat, this peat can 

 readily be converted into a cheap and valuable fuel valuable as a clean, 

 healthful fuel ; valuable, on account of its strong flame and freedom from 

 ash and clinker, as a steam generator and locomotive driver; valuable, 

 on account of its freedom from sulphur and other inetalic impurities, 

 for working iron and steel; valuable, for its fine coke producing quali- 

 ties, and the many other economic uses to which it can be put on account 

 of its fine heating properties; and cheap, because the supply of raw ma- 

 terial out of which the fuel can be manufactured is inexhaustible. 



The youngest, unripe qualities may be put to use as a fertilizer and 

 a valuable addition to the poorer prairie and hill soils. For this use it is 

 almost invaluable. Gein or humus is the fertile element in all soils. It 

 is also the life of stable and barn-yard manures. This is so well under- 

 stood in the New England States, under the scientific investigations of 

 their agricultural chemists and geologists, that peat, and even the pond 

 mucks and muds, are every year composted in large quantities, and 

 spread over the thin soils, with the happiest results. 



Agricultural chemistry has demonstrated, that the salts and gem of a 

 cord of wet, raw peat are equal to the manure of one cow for three 

 months. Practical agriculture has also demonstrated that crude peat, 

 in its raw state, is too acid and sour to be immediately beneficial to the 

 soil. By composting for a few months with wood ashes, lime, potash, or 



