70 J. A. VDDEN 



Number Feet 



1 1 . The base of the Coal Measures. 



10. Dark gray shale with lingulas near the base - - - 3 



9. Greenish shale - - - - - - - - - - iVz 



8. A layer of harder, almost stony shale ------ y^ 



7. Greenish-gray shale weathering with a conchoidal fracture into 



small spheroidal nodules and chips - - - - 1 ± 



6. Grayish, fine grained, impure dolomite - - - - - 1 y 



5. Greenish shale - - - - - - - - - -i± 



4. A thin and stony, in places highly pyritiferous seam, associated 



with small selenite crystals when decayed, in places almost 



filled with rounded specimens of Ptychtodus calceolus - tV-s 



3. Greenish shale - - ■ - - - - - - - %-i 



2. Greenish fine-grained rock with fish teeth - l A>-}( 



1. Upper ledges of the Cedar Valley limestone with a slightly eroded 



surface, frequently covered with pyrites. 



Number 10 in the above is seen in two or three places 

 farther up in the creek, but it soon disappears under the base of 

 the Coal Measures. 



Along Geneva Creek, in the northwest quarter of section 29, 

 in the same township, the basal layers of the preceding sections 

 are seen in the bed of the stream opposite the Geneva school- 

 house, and below the wagon bridge. The main stony ledge 

 forms the bed of the creek for a distance of ten or twenty rods 

 a quarter of a mile farther up. About half a mile north of the 

 schoolhouse the shale above this ledge rises some six feet in 

 the west bank, and is overlaid by the basal conglomerate of the 

 Coal Measures, from which a small spring issues. Combining 

 these exposures the succession of the layers seen may be given 

 as in the following section. 



Number Feet 



13. Basal conglomerate and sandstone of the Coal Measures. 



12. Dark gray and ferruginous, evidently somewhat disintegrated dark 



shale -.-..--------I 



11. Light greenish-gray shale -------- £ 



10. Dark lavender colored shale - - . - - - - - 1 l /e 



9. Green shaly rock ---------- y 2 



8. Concealed ---.-------? 



7. Green rock in even thin layers with regular vertical rather equidis- 

 tant joints - - - - - - - - - -1^2 



