123 



CHARACTER OF BEDS, THE THICKNESS, &.C. 



These upper uie;isures consist of very soft, lirittle and friable 

 bituminous shales holding Triarthms IJicki, Greeu and other 

 fossils. 



Band of hard compact impure limostone teeniini^ with tiie 

 remains of Conularia TrfiilonenKis, Hall, and holding also 

 Zygospira Ileaii, Bill, Leplsena sericea. Sow. Orthis testu- 

 dinaria l)al. Calymene senaria. Con., &.C., &c. 



Zone of Siphonotreta Scotica. Band of black impure bitu- 

 minous limestones gradually passing into a series of calcareo- 

 argillaceous shales, at other times compact and breaking with a 

 conchoidal fracture, holding abundance of fossils. (See lists.) 



Black and Inittle impure (calcareo-argillaceous) shales, bitu- 

 minous and holding the remains of Asa/ihus CiutaJcnxiK^ 

 Chapman. 



Band of impure limestone. 



Shales, very bituminous and brittle. 



Band of impure limestone. 



Brownish-black beds of shales, very brittle and bituminous. 



Two bands of an irregular and unevenly bedded lime- 

 stone containing Orthocerata and other fossils Init poorly pre- 

 served; limestone dark and somewhat bituminous. 



(Shales.) 

 Thirty inches. 



(Limestone) 



One inch. 



(Limestone.) 

 /one of Siphonotreta. 

 A'arics from eight to 

 twelve inches. 



(^halesT) 



(Limestone.) 



(Shales.) 



(Limestone.) 



(Shales.) 



(Limestone.) 



From the band of impuri limestone lioldlng Siphonotreta the 

 foUowinsc s[)ecie3 of fossils have also been foiiad intimately associated 

 therewith : 



1 . Batostoma erraticum Ulrich. 



2. Lingula curta, Hall. 



3. < elongata. Hall. 



4. " fjuadrata, Eichwald. 



5. Li'ptiona sericea, Sowerby. 



0. Strophomeua alternata, Coniad. 



7. Orthis testudinaria, Dalmau. 



8. Zygospira Headi, Bjillings. 

 'J. " niodesta. Say. 



10. Zj'gospira (probably a new form). 



11. Conularia Trentonensis, Hall. 



12. Asaphus Canadensis, Chapman. 



13. " platyce}ihalus, Stokes, 

 vel megistos, Locke. 



14. Calymene senaria, Conrad. 



15. Beyrichia oculifera, Hall. 



16. Leperditia cylindrica. Hall. 



A mere glance at the fauna vdiich thus characterizes the zone of 

 Slphonolreta Scotica in Americi is sufficient to indicate that the 

 measures whence thev came belong to the ITtica Formation, in the 

 u[)per portion of the Cambro-Silurian or Ordovician System. A 

 single hand s])ecimen showed the following interesting association of 

 si)ecies : ... 



1. Siphonotreta Scotica, Diiv, 3. Zygospira Headi, Bill. 



2. Lep'.JBLia sericea, Sow. 4. Asaphus Canadensis, Chap. 



