RANGE OF CHESTER OSTRACODES 



9 



formation. Two species of the new Tetra- 

 tyluSj T. ellipticus and T. elongatus, are 

 also characteristic of the Paint Creek. The 

 only other known species of this genus is 

 found in the Menard. Glyptopleurina flex- 

 uosa is sufficiently well marked to be easily 

 recognized. Perprimitia elongata is distin- 

 guished from species of Perprimitia present 

 in other formations by its elongate thin cara- 

 pace. Mooreaf circincta, distinguished by 

 its almost flat subparallel sides bordered by 

 a ridge located well in from the margins, is 

 probably the most distinctive Paint Creek 

 form. Moorites convexus is distinguished 

 from its long-range associates by its tumid 

 ovate dorsal outline and lack of a prominent 

 border around the free margins. The list of 

 restricted Paint Creek species follows : 



Species Restricted to the Paint Creek 

 Formation 



Acratia obtusa n. sp. 



Bairdia curvis n. sp. 



Bairdiolites vulgaris n. sp. 



Bythocypris modicus n. sp. 



Bythocypris ovatus n. sp. 

 *Cribroconcha fornicata n. sp. 



Healdia menisca n. sp. 



Healdia minuta n. sp. 



Healdia radinula n. sp. 



Seminolites symmetricus n. sp. 

 *Tetratylus ellipticus n. sp. 

 *Tetratylus elongatus n. sp. 

 *Beyrichia sagitta n. sp. 



Paracavellina opima n. sp. 



Paracavellina tumida n. sp. 



Sulcella celsa n. sp. 



Sulcella nodocosta n. sp. 



Sulcella ovata n. sp. 

 *Glytopleurina flexuosa n. sp. 



Ectodemites magnireticulatus n. sp. 



Ectodemites quadratus n. sp. 



Kirkbya elongata n. sp. 



Kirkbyella truncata n. sp. 



Jonesina equilatera n. sp. 

 *Perprimitia elongata n. sp. 



Sansabella ampla n. sp. 



Sansabella elongata n. sp. 



Sansabella ovata n. sp. 



Cyathus vetustus n. sp. 

 *Moorea? circincta n. sp. 

 *Moorites convexus n. sp 



HoMBERG Group 



Genera restricted to the Romberg group 

 are as follows: Golcondella, Gejfenina, 

 Kloedenella, Knightina, and Tetrasacculus. 

 Kloedenella heretofore has been known in 

 North America only from the Silurian and 

 Devonian, and Tetrasacculus from Middle 

 Devonian strata of Ohio and Michigan. 

 Knightina is a genus found previously in the 



* species of probable correlative value. 



Pennsylvanian and Permian of the mid- 

 Continent region. Golcondella and Gef- 

 fenina are not known outside of the Horn- 

 be rg group. 



The following species are found in both 

 the Golconda and Glen Dean formations 

 but are restricted to the Romberg group. 

 Those marked with an asterisk are suffi- 

 ciently diverse to form good markers. 



Glyptopleura intermedia Croneis and Gale 



*Glyptopleurina? bulbosa Croneis and Gale 

 Glyptopleurina ornata (Croneis and Gale) 

 Glyptopleurina simplex Croneis and Bristol 



*Glyptopleuroides insculptus Croneis and 

 Gale 



"*Amphissites carinatus n. sp. 



*Jonesina craterigera (Brady) 



*Tetrasacculus mirablilis (Croneis and Gale) 



Golconda formation. — Approximately 

 half of the 36 restricted Golconda species 

 are new, but some of these are sufficiently 

 abundant and distinctive to make good 

 horizon markers. Monoceratina celsalobata 

 n. sp. is distinguished from other species of 

 Alonoceratina by its low thick form and the 

 relatively high position of the spines as seen 

 in lateral view. Beyrichia contracta n. sp. 

 and B. placida Croneis and Gale are Gol- 

 conda species, and the only other Chester 

 representative of this genus is B. sagitta 

 n. sp. from the Paint Creek. Glyptopleura 

 decacostata Croneis and Gale may be recog- 

 nized by the pronounced forward swing 

 and the relatively wide area free of costae 

 at the posterior end. Denisonia brevicosta 

 n. sp. and Z). cirrata n. sp. both possess 

 shells with a pronounced swing, with un- 

 equal ends, and with a relatively short rid^T^e 

 in the middle of the shell. The single Me- 

 nard species lacks the swing, has a long 

 ridge, and has ends of equal height. Other 

 species which seem distinctive are Golcon- 

 della sulcata, Glyptopleura pentacostata, 

 Glyptopleurina vetula, and Geffeninaf 

 praelonga. 



The complete list of restricted Golconda 

 species follows: 



Species Restricted to the Golconda 

 Formation 



*Monoceratina celsalobata n. sp. 



Bairdia? osorioi Croneis and Gale 



Bairdia cf. subelongata Jones and Kirkby 



Bythocypris opima n. sp. 



Healdia cornigera (Jones and Kirkby) 



Healdia elliptica n. sp. 



Healdia mucronata n. sp. 



Healdia opima n. sp. 



Seminolites? reversus n. sp. 

 *Beyrichia contracta n. sp. 



