Geology of Upper Illinois. 145 



To the traveller who enters the Illinois valley at Ottawa, after 

 having been satiated with the boundless views of rolling prairie, 

 no scenery can be more novel and enchanting, than that which 

 he beholds between the month of Fox river and the town of 

 Rockwell. The first striking object he encounters after leaving 

 Ottawa, is Buffalo-rock, an interesting plateau, whose top corres- 

 ponds in level with the high prairie, and whose sides are equally 

 precipitous with the main bluffs of the valley. The area of Buf- 

 falo-rock is about one square mile. The river sweeps directly past 

 its southeastern base ; while the canal, as will appear from the 

 map, is carried along between it and the north bluff of the valley. 

 At a distance of about a mile from this insular elevation of prai- 

 rie, and directly by the road-side, is situated one of those beauti- 

 ful mineral springs (of whose chemical constitution we shall 

 presently speak,) for which this part of Illinois is remarkable. 

 Two springs break out within a distance of a rod, both of which 

 occupy the same basin-like depression, whose surface is about five 

 feet lower than that of the adjoining bottoms. The larger of 

 these two springs discharges at least ten gallons of water per min- 

 ute, and rising through a bed of fine white sand, (which it keeps 

 in constant agitation,) forms a very striking object. The water 

 fi*om the springs, after flowmg a distance of fifteen rods over the 

 bottoms, falls into a rocky channel worn out of the sand-rock, 

 along which it rapidly descends for a couple of rods farther, where 

 it enters the river, but not before it has received the water of an- 

 other spring whose issue is from between the sandstone layers. 

 Two miles after leaving the springs, the traveller is opposite the 

 tragically famous Starved Rock.* It forms a part of the bluff on 

 the south side of the Illinois, projecting promontory like, quite 

 into the bed of the river, and rising twenty or thirty feet higher 

 than the average level of the bluffs. Its face towards the river 

 is perpendicular, and even overhanging. On some of the maps 

 of the county its height has been stated at two hundred and fifty 

 feet, which is certainly incorrect, — it having recently been meas- 

 ured by Mr. O. W. Jerome, civil engineer of Rockwell, who finds 

 its elevation one hundred and forty feet above the level of the II- 



* About one hundred years since, a ferocious tribe of Indians, being driven by 

 their enemies upon this projecting point of the Illinois bluff, were reduced to 

 submission by actual starvation. 



Vol. XXXIV.— No. 1. 19 



