214 , GEOLOGY OF ILLINOIS. 



Probably near the same level, possibly a little higher, belong the loose, vescu- 

 lar layers in the bed-rock of the creek, at the north-west corner of section 8, 

 town 34 north, range 11 east. The rock is not such as to invite quarrymen, 

 but a local supply, for fences, wells and underpinning, can be drawn from near 

 the west line of section 19, of this township, and the southeast corner of section 

 13, in the adjoining township ; and more extensive quarrying in the low ground 

 would, undoubtedly, develop beds of fair building stone. At present, this is 

 hauled either from the Jackson quarries, near the center of section 15, town- 

 ship 34 north, range 10 east, or from those at Joliet. 



The beds which form the bluffs on both sides of the DesPlaines, at and near 

 Lockport, belong at and below this level. Opposite Lockport, the bluff shows, at 

 intervals, from fifty to sixty feet of these beds, which are mostly thin, and more 

 or less vesicular, containing imperfect impressions of fossils. The upper part 

 of these beds is passed over in going east from Lockport, and the fragments loose 

 in the soil indicate that they lie not far below the surface ; but the only outcrop 

 seen is in the bed of a small stream near the southwest corner of section 2, town- 

 ship 36 north, range 11 east. At several points, these beds are used for lime, 

 and yield a very fair article. The lower part of these beds contain several lay- 

 ers of chert nodules, often accompanied by a chalky substance. (Messrs. A. 

 Hyatt and E. Bicknell, of the Peabody Academy of Science, Salem, Mass., have, 

 at my request, examined portions of these cherts, microscopically, but have not, 

 as yet, succeeded in finding any organisms except sponge-spicula.) These flinty 

 layers form a ready means of determining a general equivalence of level, though 

 they extend through a considerable thickness of rock, which varies in amount 

 at different localities. I consider them sufficient, however, to synchronize with 

 these beds those that are quarried extensively in the southeast quarter of sec- 

 tion 2 and the northeast quarter of section 11, township 36 north, range 9 east. 

 Here I include, also, the beds quarried to some extent in the southwest quarter 

 of section 26, and the northwest quarter of section 35, township 37 north, range 

 9 east. 



The top of the quarry, in the southeast quarter of section 11 of the Jast 

 named township, belongs at the bottom of the foregoing Jjeds, while the lower 

 part of it reaches the solid blue quarry rock which lies next below. Some 

 thin beds of this rock have been quarried to a small extent, in the southwest 

 quarter of section 31, township 36 north, range 10 east. Its lower portion 

 underlies the DesPlaines valley, from the county line to below Lockport, and 

 furnishes the quarries so extensively worked between Lockport and Joliet. 

 The Jackson quarries, before mentioned, are at nearly the same level. These 

 beds are also extensively quarried in "Twelve-mile Grrove," near the center of 

 section 10, township 33 north, range 11 east, and the lower part of the bed is 

 seen in the bottom of Forked creek, in the southwest corner of section 21 of 



