348 W. H. Twenhofel — Pre-Cambrian and 



13. Nodular, gray shaly limestone with numerous fragments 

 of fossils. Bedding irregular. Contains many coenoplases of 

 Lithothamnium-like algae 2 feet 5 inches. 



12. Gray nodular limestone, weathers yellow. Very fossil- 

 iferous, containing Derbya, Bellerophon, Productus, bryozoa, 



coenoplases of Lithothamnium-like algae and other fossils 13 



8 inches. 



11. Concealed, probably shale 15 feet. 



10. One bed of thin, fine-grained gray limestone 



4 to 6 inches. 



9. Concealed 6-5 feet. 



8. One bed of gray limestone, generally seen as slabs on the 

 slopes 8 to 10 inches. 



7. Concealed, supposedly shale 16 feet. 



6. One bed of gray limestone 12 to 14 inches. 



5. Gray limestone with poorly defined bedding 3 feet. 



4. Mostly concealed, presumably shale, but contains a little 

 limestone 15 feet. 



3. Brittle gray limestone, irregularly bedded 4 feet. 



2. Gray limestone, irregularly bedded and full of Fusulina 

 1 foot. 



1. Shaly, nodular gray limestone 2 feet exposed. 



The algal deposits were not seen elsewhere than in the 

 zones in which they have been noted and their occurrence 

 may be coextensive with the distribution of these zones, 

 but because of the weakness of the rocks of which they are 

 composed, exposures are rather uncommon so that the 

 algal material was not seen in very many places. 



Only a single species of alga appears to be repre- 

 sented, and it apparently belongs to an undescribed 

 genus. The incrustations about the fossils of zone 14 

 probably belong to the same species. 



Ottonosia new genus. 



Irregularly shaped coenoplases which begin as incrus- 

 tations around other substances and increase in size 

 through the deposition of material over and around that 

 already deposited. The diameters vary up to about 85 

 millimeters. Most of the coenoplases are biscuit-shaped; 

 a few are spherical. In small specimens the shapes 

 appear to have been determined by the shapes of the 

 nuclei. One specimen which has the convex valve of a 

 Derbya for a nucleus still retains that shape, the shell 

 being covered with about one eighth inch thickness of 



13 Zones 12 to 17 constitute the Crouse limestone. 



