32 PROCEEDIISrGS OP THE NATIONAL MUSEUM vol.76 



the upper portion of the Thunder Bay stage of eastern Michigan. 

 The reference of these beds to the Olentangy shale of Ohio has long 

 been known to be incorrect, and on the grounds here discussed the 

 lower portion of the Ontario section is necessarily considered an 

 eastward extension and integral part of the Thunder Bay stage of the 

 Traverse group. A number of closely differentiated species common 

 to the Thunder Bay stage of Michigan and the lower portion of the 

 Ontario section are cited below. 



Cystiphyllum ahoreum Grabau (chironym). 

 Ceratopora cf. partita (Winchell). 

 Cladopora {Cocnites?) fisheri (Billings). 

 Trachypora (?) pro'boscidialis (Roniinger). 

 Alveolites sulramousus Rominger. 

 Scalaripora separata Ulrich. 

 S. approximata Ulrich. 



Fistulipora (? DicJwtrypa) corrugota Ulrich. 

 F. stellifera Ulrich. 

 Chonetes near scitula Hall. 

 C. near vicina (Castelnau). 

 Pentamerella, new .species. 

 Tentaculites attenuatus Hall (var.) 

 Spirit er arkonense Shimer and Grabau. 

 Cyrtina species near hamiltonensis Hall. 

 Cystodictya near incisurata (Hall). 

 Megistocrinus concavus Wachsmuth. 



Collections from the lower beds of the Thunder Bay of Ontario 

 are incomplete at present but further additions are certain to bring 

 to light much if not the entire fauna contained in the strata at 

 Partridge Point in Michigan. 



Having established the identity of the Thunder Bay strata in 

 Ontario we find them capped by true Hamilton beds overlapping 

 from the New York province. This is the most westward occur- 

 rence of beds belonging undeniably to the New York Hamilton, 

 and they fortunately can be placed accurately in the generalized 

 section of that State. The "Encrinal limestone " and the " Coral 

 Bed " of the Widder beds, so classic for their abundant and beautiful 

 fossil remains, are identical with the same beds of the East Bethany 

 section described by Slocum.^° The occurrence of these strata at 

 the latter locality is found at the long railroad cut a mile and a 

 half west of the station at East Bethany. Slocum, however, in 

 collecting the abundant remains from the talus of this locality mis- 

 took the position of the " Coral Bed " to lie below the " Encrinal 

 limestone." Subsequent work at this place has established the fact 

 that the beds under discussion hold the same reference to each other 

 as they do at Arkona and in vicinity of Thedford in Ontario, 200 



=«> Slocum, A. W. Field Col. Mus. Publ., vol. 2, pp. 257-265, 1906. 



