GEOLOGY OF SOTTTHWESTEEN IOWA. 333 



No. 3. Light colored silicious shaly marl 2 feet. 



No. 2. Compact, thin-bedded grayish limestone 7 feet. 



No. 1. Hard, shaly, marly clay, with thin bands of impure lime- 

 stone 4 feet. 



Total 13 feet. 



The base of No. 1 was not seen, being covered by the water 

 of the creek. Abont a mile further up the valley, on section 

 11 of the same township and range, and in the left bank of 

 the river, abont ten feet in thickness of uniformly bedded 

 limestone is seen, resting upon about five feet in thickness of 

 bluish, fragmentary, argillaceous, limestone; the latter very 

 fossiliferous. 



Continuing np the valley about Fig. 24. 



three miles farther, at Emerson's 



mill, on section 31, township 71, 7 J|||||||||g|l| y 



range 28, the following named strata 



10' 



were found exposed in the left bank s 



of the river and are represented ,_ ^f^ ~'y = ^r = ^~ = r^Z' )i , .e" 



by Fig. 24. 



Section at Emersorts Mill. 



No. 7. Yellowish, impure limestone, with frequent partings of 



calcareo-silicious shale of same color 7 feet. 



No. 6. Bluish, clayey shale, with occasional thin concretionary 



layers of impure limestone 4 feet. 



No. 5. Black carbonaceous shale 1 foot. 



No. 4. Bluish shale, very fossiliferous. . . y-f feet. 



No. 3. Bluish clayey shale 2^ feet. 



No. 2. Rough, greyish limestone 1^ foot. 



No. 1. Grayish, clayey, and concretionary limestone 1% foot. 



Total 18^ feet. 



The water in Grand river reaching No. 1, no strata were 

 seen beneath it. This lowest member of the section is largely 

 composed of the shells of a very small variety of Fusulina 

 cylindrical and the clayey partings of the layers of lime- 

 stone are crowded with the same fossil. 



