EI/ISHA MITCHELL SCIENTIFIC SOCIETY. 65 



EXPLANATION OF PLATES. 





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Fig-. 1. Section throug-h reg-ion of Palceotrochi.s Beds. After Emmons. 



Fig-s. 2, 3 and 4. Palceotrochis minor. After Kmnions. 



Fig-s. 5, 6, 7. Specimen found b^' Emmons, in possession of Prof. Col- 

 lier Cobb. 



Fig-s. 8 and 9. Palceotrochis major. After Emrnons. 



Fig-. 10. Showing- position of fossils in bed. 



Fig-. 11. Pal(sotrochis deformed and fractured by pressure. 



Fig-. 12. Microscopic section showing- fracture. 



Fig. 13. Microscopic section showing- chalcedonic envelope. 



Fig-. 14. Polished surface of rock showing- layers of deposition in 

 specimen. 



Fig-. 15. Falcrotrochis showing- what Emmons described as budding-. 



Fig-. 16. Spong-e. 



Fig-. 17. An org-an of medusa. 



Fig-. IS. Sug-g-estion as to possible arrang-emant o± palcsotrochis. 



