GEOLOGY OF SOUTHWESTERN IOWA. 379 



Section at Stutsman's Mill. 



No. 3. Layer of grayish limestone x| foot. 



No. 2. Light bluish, shaly clay 4 feet. 



No. 1. Grayish limestone 10 feet. 



Total 14j-f feet. 



Going up the east side of the valley about a mile above the 

 old mill, several exposures of limestone are seen in the 

 valley-side, comprising six or eight feet in thickness of 

 grayish limestone, crowded with the shelly remains of 

 Fusulina cylindrica. At the water's edge in the same 

 vicinity, and of course holding a position beneath the lime- 

 stone, some slight exposures of carbonaceous shale and 

 calcareous fossiliferous clay were observed. The inhabitants 

 report the existence at the last named locality of a thin seam 

 of coal near the bank of the river. This was not seen, but 

 since the strata there occupy about the same horizon as 

 the Nodaway valley coal-bed, it is not improbable that such 

 a seam exists there, yet it is thought improbable that it will 

 be found of profitable thickness. 



Going westward to the valley of Mosquito creek we find in 

 its left bank, about three miles west of Council Bluffs, some 

 important exposures of limestone with marly partings, 

 presenting a vertical thickness of about seven feet, all of 

 which are referred to the same horizon as the exposure below 

 the mill near Lewis. Important quarries have been opened 

 here for obtaining building material and for lime-burning. 

 Some of the upper layers are flinty, like some of those at 

 Lewis, and considerable quantities of flint are mixed in the 

 very slight deposit of drift that occurs here, which has a 

 thickness of only two or three feet in some places between the 

 Bluff Deposit and the limestone. 



Six miles north of Council Bluffs, there Fig. 43. 



is another exposure of the same lime- 

 stone, and apparently representatives, in 

 part, of the same layers just mentioned. 

 The exposure is at the base of the bluffs f rf^s^jz^—),/ G > 



