338 CHARLES S. PROSSER 



Thickness tJSss 



No. Feet Inches Feet Inches 



23. Brownish- to bluish-gray, thin layer, from 1 to 



2 inches thick i|± 17 6 



22. Bluish-gray shaly limestone to shale, from 6 to 7 



inches thick. A specimen of Leptaena rhom- 



boidalis (Wilckens) was noted . 6§± 17 45 



21. Dayton limestone. — Top layer of western bank 

 of the Colonel Samuel B. Smith quarry. Light 

 gray, with rusty spots due to iron pyrite, from 



3 to 4 inches thick 3^ ± 16 10 



20. Layer 2± inches thick 2 ± 16 6| 



19. Layer from 3 to 4 inches thick with dark-gray 



blotches in its upper part 3§± 16 4^ 



18. Dark -gray irregular bands in the lighter colored 

 rock. It contains iron pyrite and varies from 



4 to 5 inches in thickness 4§± 16 1 



17. Light-gray rock without much dark color, 



which contains some iron pyrite and varies from 



5 to 6 inches in thickness 5^± 15 8J 



16. Three-inch layer at bottom of more or less 



massive zone (Nos. 16 to 21, inclusive), with 



average thickness of 1 foot 10 inches at top of 



quarry wall on the western and northern sides. . 3 15 3 



15. Two rather compact layers, the upper one 4 



inches and the lower, 6 inches thick . . : 10 15 o 



14. This layer will split up into thinner ones and it 



contains iron pyrite 9 14 2 



13. Compact layer 4 13 5 



12. This layer may split up to some extent on 



weathering . ! 9 13 1 



11. This layer on weathering splits into various 



layers from 2 to 5 inches thick 1 2 12 4 



10. This layer on weathering tends to split into 



layers from 2\ to 4 inches thick 9 11 2 



9. Layer with dark -gray blotches or banding due 



to iron pyrite 6 10 5 



8. Layer from 5 to 6 inches thick, which tends to 



split to some extent and contains masses of 



calcite ♦ 5I ± 9 11 



7. Six-inch layer with stylolites structure in the 



basal portion 6 9 5! 



6. The limestone of this layer and the underlying 



Dayton layers is, in general, compact, probably 



