46 



deeply divided. All the margins of the lobes and sinuses are charac- 

 terized by small, rounded serrations. Siphuucle of moderate size, mar- 

 ginal and situated between the lines of nodes. 



The distinction between this and the preceding species consists in 

 its large size, more robust habit, and thicker shell, and in the more 

 distant and much more complicated septa. It is still further removed 

 by these characters from P. Mortoni M. & H., as well as by the simple 

 ridges. 



Formation and locality. In limestone of the Fort Pierre group, on Old 

 Woman's Fork, Black Hills. 



LIST OF FOSSILS DESCRIBED IN THE KEPOKT OF THE 

 PALEONTOLOGY OF THE BLACK HILLS. 



POTSDAM GROUP. 



Name. 



Locality. 



Palseochorda prima, D. sp 



Pal reopb yens occidentals, D. sp, 

 sp, uudet 



INCERTECEDES. 



Scolitnus, sp. 



BRACHIOPODA. 



Lingulepis piunaformis, Owen 



cuueolus, n. sp 



perattenuatus, n. sp 



Dakotensis, Meek & Hayden 



Obolus ? pectenoides, Whitf 



Obolella polita, Hall 



Obolella naua, M. & H 



CRUSTACEA. 



Crepicephalus (Loganellns) centralis, n. sp. 

 planus, n. sp .. 



Head of Red Water Valley. 

 Do. 

 Do. 



Warren's Peak. 



Red Canon Creek. 



Do. 



Do. 

 Castle Creek. 



Do. 

 Red Water Canon. 



Do. 



Castle Creek. 

 Do. 



JURASSIC. 



RAD I AT A. 



Asterias? dnbium, n. sp 



Pentacrinus asteriscus, M. & H. 



BRACHIOPODA. 



Lingula brevirostris, M. & H... 

 Rbynchonella inyrina, H. &. W 



Spear's Fork of Red Water Creek. 

 Big Horn Mountains. 



Spear's Fork of Red Water Creek. 

 Red Canon Creek, 



