Geology of Upper Illinois. 157 



ing and evaporating fluids. It will also give rise to a coke of 

 a medium quality, the presence of iron-pyrites not being found so 

 considerable as to interfere with its employment by the black- 

 smiths of the country, who prefer it indeed in their work, to 

 charcoal. 



Mineral Springs and Salt. 



Sulphureous and saline waters appear to be of frequent occur- 

 rence in the region of the coal-deposit above described. Copious 

 springs occur at and near Ottawa, particularly on the Illinois bot- 

 toms in the vicinity of Buffalo rock. Others again exist in the 

 bed of the Big Yermilion, at Vermilionville, and near the mouth 

 of the Mazon river. 



The springs on section twenty three (H,) have already been 

 alluded to. The two which come to the surface near together, 

 and by the road-side, may be denominated saline waters. Their 

 temperature was apparently above that of other springs in the vi- 

 cinity, and decidedly superior to the mean temperature of the cli- 

 mate. No odor of sulphuretted hydrogen is evolved from either 

 of them, nor do they blacken a solution of acetate of lead. The 

 application of the usual tests, proved them to contain the follow- 

 ing principles : — 



Carbonic acid. 

 Nitrogen. 



Super-carbonate of lime. 

 Bi-carbonate of soda. 

 Chloride of sodium. 

 ^' of calcium. 

 " of magnesium. 

 Sulphate of lime. 

 " of magnesia. 



* "of soda. 



The spring issuing from the sandstone layers, nearly on the 

 bank of the Illinois, is a strong sulphureous water ; and in addi- 

 tion to the above enumerated ingredients, contains free sulphur- 

 etted hydrogen and the hydro-sulphuret of sodium. 



Both these springs were tested for iodine and bromine, with- 

 out discovering either of these substances ; although the ex£im- 

 ination was made on less than a gallon of water. If these prin- 

 ciples are present therefore, their proportion must be inconsidera- 

 ble, compared to the other ingredients. 



