417 



Mono. 



gian ( Olenellus) zone is placed beneath the Braintree {Para- 

 el oxides) zone as Lovjer Cambrian^ this and certain other tri1o- 

 biles are kept in the Middle Cambrian, (MS. letter, Dec. 

 1888.) — M, C. — See Appendix. 



Monocraterion lesleyi. Prime. Report, Geol. Sur. Penn- 





.fH- 



i^ 







I. i.tA-ir .7 J 





-I<c»-'^"**»^ 



4* yTv^r^-<' 



sylvania, in Northampton county, DD, 1878, page 79, 80, plate 

 27 



