GEOLOGY OF SOUTHWESTERN IOWA. 365 



Going northward, from Stennett's into Cass county, both the 

 Cretaceous and Upper coal-measure strata are again found 

 exposed and will be represented in the geology of that 

 county. Going southward, an exposure of the Cretaceous 

 sandstone is found on land of Mr. Johnson, section 2, town- 

 ship 72, range 38. It occurs in the bank of a small rivulet 

 which comes into the Mshnabotany from the eastward. It 

 consists of about thirty feet in thickness of the usual coarse 

 soft sandstone, resting upon variegated, or red and grey 

 mottled clay. No other strata were found in connection with 

 these at that locality. At Red Oak village a couple of expo- 

 sures of the same sandstone are found, each measuring some 

 eight or ten feet in thickness, and in the same vicinity Upper 

 coal-measure strata are exposed which occupy both higher 

 and lower levels respectively than the sandstone does, 

 showing conclusively the unconformabili ty of the latter upon 

 the former. Those referred to as being above the level 

 occupied by the sandstone are regar- FiG 3? 



ded as equivalent to the upper part of ^ __.^, 



the section at Stennett's, beneath the jE^zz^r 



sandstone there, while the lower gSS^SSi 



strata at Red Oak are lower than any ^Me^^WK/ 20 ' 



seen at Stennett's, and doubtless, the J^^MM^m 



lowest exposed in the county. They ,^§p@|S5R§S^) 



are probably equivalent to the lower / & ^ — ~-±- '" ' " ~zx s 



members of the section in the valley of the Tarkeo in Page 

 county. Fig. 37 represents those lower strata in the banks of 

 the Mshnabotany at Red Oak. 



Section near Red Oak. 



No. 2. Fine grained sandj r and clayey micaceous shale 20 feet. 



No. 1. Bluish compact impure limestone 1^ feet. 



Total 21 1£ feet. 



~No 1 was found exposed just at the water's edge. At the 

 top of No. 2 reddish and bluish clays were obtained in a 

 disturbed condition by weathering. They are very similar in 



