112 GEOLOGY OF ILLINOIS. 



for cellar walls, foundations and other similar uses. Killbuck creek 

 running north through the south-eastern portion of the county, cuts into 

 the same rock and even touches the Blue limestone, but no good outcrop 

 is shown. About Payne's Point, in the township of Pine Eock, along a 

 little timber ravine, stone are quarried, whose conchoidal fracture and 

 ash color show beds of passage between the Galena and the Blue. 



North of Rock river the same phenomenon is observed, only on a more 

 extensive scale. The older formations sink as the distance from the 

 stream increases, until the Galena runs on, forming surface rock where 

 the river enters the county 7 , but, before reaching Byron, it strikes these 

 older formations. Leaf river and Pine creek cut deep into the surface 

 deposits, and show outcrops of the St. Peter's sandstone, the Buff and 

 Blue limestones respectively for some distance after the Galena becomes 

 the underlying rock of the surrounding country ; but even along the 

 banks of these streams, the Galena outcrops long before their sources 

 are reached. All round the headwaters of Leaf river the gravel beds 

 rest directly upon the Galena limestone. The road from Polo to Mt. 

 Morris crosses Pine creek about the middle of its course. At the cross- 

 ing, Galena escarpments, crowned with the white pine and red cedar, 

 overhang the creek as it washes their base. In going down stream the 

 Blue Trenton is soon struck ; but in going up stream, even to its very 

 sources, massive time-worn outcrops of the real lead-bearing rocks add 

 picturesqueness to the scenery. At the forks of Pine creek, a few 

 miles north west of the residence of Hon. D. J. Pinckney, there is an 

 outcrop thirty-six feet thick, the upper half of which is quarried into. 

 A lime kiln is here in successful operation ; and stone is quarried for 

 common building purposes. 



The western part of the county, between the Illinois Central Eailroad 

 track and county line, are principally underlaid by the limestone under 

 consideration. Elkhorn creek, which just touches the county about 

 Brookville, and Buffalo creek, a small stream west of Polo, both cut 

 into the Blue limestone as the exceptions to the above statement. At 

 the quarry one mile west of Polo, on the Mt. Carroll road, the Galena 

 composes the top layers ; the middle is beds of passage, and the bottom 

 is the Trenton Blue. Following the creek down past the large Blue 

 limestone quarries south-west of Polo, the Galena is again struck before 

 the county line is reached, and at Sanfordsville, a short distance beyond 

 the county line in Whiteside county, displays itself in a massive quarry, 

 worked extensively in former days. The same rock prevails about Woo- 

 sung. 



At White Eock and at the forks of Pine creek a few characteristic 

 fossils were to be seen ; but the rock is not worked enough in this 

 county to afford many fossils or good specimens. Where a Galena 



