Geabau — Faunas of the Hamilton Group. 



291 



III. THE LOCAL FAUNAS AND SUBFAUXAS AXD THEIR 

 SUCCESSIOX IX THE HAMILTOX GROUP OF THE 

 EIGHTEEN-MILE CREEK REGIOX. 



A. The upper Marcellus. 



a. The fauna of the Transition shales. 



The thirty feet of shale overlying the Pteropod bed of the Marcellus, 

 while presenting true Marcellus characters in their fauna, nevertheless 

 approximate to the overlying Hamilton sufficiently to warrant their being 

 regarded as in a measure transitional from the typical Marcellus to the typical 

 Lower Hamilton shales, and for that reason they are discussed here. 



The following is a complete list of the fossils obtained from these 

 shales : 



Crustacea : 



*1 Phacops rana. r 

 2 Cryphaeus Boothi. r 

 6 Primitiopsis punctulifera. r 



Cephalopoda : 



Orthoceras sp. r 



Pteropoda : 



14 Tentaculites gracilistriatus. c 



15 Styliolina fissurella c 



Gasteropoda : 



25 Euomphalus (Phanerotinus) laxus. R 

 33 Bellerophon Leda. R 



Lamellibranchiata : 



53 Xuculites triqueter r 

 61 Lunulicardium fragile, c 



Brachiopoda : 



87 Orthothetes arctostriata. I 

 96 Chonetes mucronata. r 



*The numbers preceding the name correspond to those given in Part II. R=very rare, r=rare, rc=fainy common, 

 C-Common, C=very common. 



