80 IOWA ACADEMY OF SCIENCE 



FEET INCHES 



color. Some of the lumps consist of 



an external shell with an included 



structureless nucleus 9 



3. Shale, blue, arenaceous 5 



2. Sandstone, blue, indurated, micaceous, 



and ripple marked 2 



I. Shale, arenaceous 1 



Total 24 



The limestone near the reservoir at the foot of the bluff was the 

 foundation wall of a building that had been removed. 



During the past summer slumping has covered some of the 

 lower strata at McKissisks Grove ; however, active erosion at the 

 head of ravines has revealed details of strata not before observed. 

 The outcrops at this locality are seen successively by following 

 an unnamed creek to the forks, then the east branch about one- 

 fourth mile ; on the south branch are several excellent exposures 

 within a distance of one-half mile. All these outcrops are easily 

 fitted with each other. 



COMPOSITE SECTION AT McKISSICKS GROVE. 



FEET INCHES 



19. Shale, blue 12 



18. Shale, gray, weathered 8 



17. Limestone, very dark gray, arenaceous, 

 many spheroidal lumps, in places 



brecciated 1 



16. Limestone, blue, very arenaceous, might 



be termed a calcareous sandstone. ... 1 



15. Shale, arenaceous, micaceous 3 



14. Sandstone, blue, weathering yellow fc 



13. Shale, arenaceous, micaceous 2 6 



12. Sandstone, blue, weathering yellow 1 



II. Shale, gray 9 



10. Limestone, dark gray, fossiliferous, in 



two layers 3 



9. Coal, Nyman 1 



8. Shale, yellow and blue 31 



7. Limestone, gray, fossiliferous 6 



6. Shale, dark gray 3 6 



5. Limestone, very dark gray 6 



4. Shale, blue weathering to yellow 8 



3. Limestone, weathered brown. In two 



or three layers. Tarkio 4 



2. Shale, gray, weathered 12 



1. Limestone, dark gray 1 



Total 110 



