LEE COUNTY. 127 



for one, two, or three miles. Ou the east, north and west of these sand- 

 stone bluffs, the formation terminates abruptly, sinks out of sight 

 rapidly, and seems like an abrupt auti-clinal axis pushed boldly up into 

 the air. On these sides the overlaying formations are piled as it were 

 against the sides of this sandstone uplift. But on the south side it 

 sinks away more gradually, and doubtless is the underlaying rock for 

 most of the distance in a south-east direction to the great upheaval at 

 Deer Park and Starved Eock, on the Illinois river. A line drawn from 

 the mouth of Franklin creek up that stream, thence on a south-east 

 course to the south-east corner of Lee county, and thence to the Illinois 

 river through La Salle county, for most or all of that distance, would 

 pass over this deposit, lying almost or immediately under the drift de- 

 posits. A line from Oregon city to the same point, or lines from inter- 

 mediate points on Eock river to the same point, would pass over forma- 

 tions almost identical. From the uplift on Rock river to that on the 

 Illinois river, there is probably a low axis of elevation somewhere in 

 the section of country bounded by the above imaginary lines. I have 

 no doubt but that a broad strip of Lee county, extending from Grand 

 DeTour to the north-west corner of La Salle county, is underlaid by the 

 St. Peter's sandstone. About Franklin, and even south of that, this 

 strip may be covered with fragmentary patches and tields of overlaying 

 Silurian formations : but artesian wells for all this distance would soon 

 strike the St. Peter's sandstone, after passing through the overlaying 

 drift. 



The next visible outcrops of this formation in Lee county, may ! 

 ou Franklin creek. Several of these may be noticed, commencing about 

 two miles below the village of Franklin, and showing themselves in the 

 base of the creek bluffs all the way down to Rock river. The outcrops 

 are low, and are sometimes capped by Buff and Trenton limestones. 



These are the natural outcrops of the St. Peter's sandstone in Lee 

 county. Along the northern line of the county, and east of Franklin 

 creek for a few miles, other low-lying outcrops may exist. If so, I did 

 not notice them: and they possess no peculiar interest. 



This sandstone has often been described. Its varying shades of color, 

 from white to dirty brown, rusty, and almost name-red, are well known 

 to all observers in its vicinity. Its want of cohesion, saccharoid, almost 

 crumbling appearance, would seem to indicate that atmospheric and 

 chemical agencies, such as the rain, the winds, the frost, and the tooth 

 of time, would speedily level its piled up sands and strew them far and 

 wide : but this is contradicted by its remarkable property to weather 

 into sugar-loaf shaped hills, rau-v.l pinnacles, and gracefully rounded 

 bluffs, able to preserve their form and shape through the rolling years. 



