KENDALL COUNTY. 143 



further down stream, at the ford and below, the bed of the creek is composed 

 of a bluish-gray, thin-bedded limestone, which is likewise fossiliferous. By a 

 boring which was made by Mr. Durst, at his place, near the center of the west- 

 ern line of section 22, and half a mile from the creek, the following section was 

 afforded : 



fEKT. 



1. Surface soil and clay 7 



2. Hard, bluish-gray limestone reported by Mr. Durst to be the same as that occurring 

 at the crossing of the AuSable, half a mile west 17 



3. Hard, thin-bedded, bluish limestone, with shaly partings, said to contain, in its upper 

 portion, about two inches of black, coaly matter, probably bituminous shale 54 



I have not positively identified the lowest beds (No. 3) of this section, in any 

 of the surface outcroppings along the creek, although they probably appear at 

 some points in its bed farther down stream, in this or the adjoining county. 



Below, this point, the rock does not appear continuously in the bottom and 

 banks of the stream, but is covered in most places with mud and gravel. The 

 nearest points where it appears prominently in the bed of the creek, are the 

 southwest corner of section 23 and the center of section 27. In both of these 

 places, at the time of my visit, the stage of water was such that the strata were 

 not visible, but, from pieces thrown out upon the bank, I considered the rock 

 in this place to be the same as that in the localities above named. Further 

 down stream, at the crossing of the old stage road from Joliet to Ottawa, just 

 west of the center of section 34, I observed ledges of thin-bedded limestone 

 appearing in the bank, to the hight of three feet or more above the water. The 

 upper beds are light gray, inclining to a buff color, while some of the lower 

 layers are dark gray and bluish. At the county line, a half mile further south, 

 rock again appears in the bed of the creek a highly fossiliferous, bituminous 

 limestone, dark colored, almost black on freshly fractured surfaces. The gen- 

 eral dip of the strata, in all these localities, is toward the northeast, although it 

 is so slight as not to be everywhere apparent. 



Trenton Group. This formation, consisting, as has been stated, of heavy- 

 bedded, yellowish and blue limestone, occupies all of that portion of the county 

 which has not already been described as underlaid by the more recent forma- 

 tions, with the exception, perhaps, of a very small fraction of township 35, range 

 6, in the southwestern part, which may be underlaid by the St. Peters sandstone. 

 Its outcrops are confined to the banks of Fox river, and a small area in the 

 southern part of the county, in township 35, ranges 6 and 7. 



At Post's mills, near the mouth of Big Rock creek, in the southwestern part 

 of section 34, township 37, range 6, a quarry has been opened in this rock, to 

 a depth of almost five feet. It is here a light buffer yellowish, porous limestone, 

 the more solid portions showing a grayish hue on freshly fractured surfaces. 

 The beds lie apparently level, as no dip in any direction is perceptible at this 



