GKOLOGY OF LA SALIyP: COUNTY. 



51 



rietals — -Iron exists in small quantities as pyrite 

 (bisulphide), hematite (red oxide), limonite yellow 

 oxide and iron stone or carbonate. 



Copper has been found in the drift, especially 

 in the Fox river valley, near Dayton, evidently brought 

 from the lake Superior' regiofi during- the o-lacial 

 period. 



Lead has been found in the form of Galenite (sul- 

 phide) in the Trenton, throug^h which rock it seems 

 sparing-ly disseminated, but no one need expect to find 

 lead mines in La Salle county. 



Mineral Waters— The county contains numer- 

 ous mineral spring-s, the most widely known the 

 Ottawa mineral spring* and the sulphur spring- or 

 springs situated about six miles west of Ottawa, 

 on the river road, on the north side of the Illinois. 

 The Ottawa spring- is the only one whose waters have 

 been analyzed. Its composition is g-iven in the ap- 

 pendix. 



The sulphur spring's, three in number, carry con- 

 siderable quantities of sulphur and sulphuretted hy- 

 drog-en g-as, but as no anal3^sis of these waters has 

 beer made little can be said of their therapeutic value. 

 Many 3^ears since a larg-e building- for a hotel was 

 erected near them and an effort made to bring* them 

 into notice, but it did not immediately pay and the 

 attempt was abandoned. The Ottawa spring* has had 

 nearly the same fate, but its water is in some demand, 

 and seems to possess, and we presume the same is true 

 of the other, considerable medicinal value. 



A water very similar, if not precisely the same, is 

 found on the east side of the creek, about a half mile 

 south of the Covell creek bridg*e, on the river road; 

 also in the second canon east of Starved Rock. 



