42 THE DEVONIAN OF MISSOURI. 



Stropheodonta mflexa Swallow (c) Euomphalus cf. hecale Hall (r) 



Stropheodonta navalis Swallow (c) Pleurotomaria isaacsi Hall and Whit- 



Strophonella crassa Rowley (r) field (c) 



Vermes Cephalopoda 



Spirorbis omphaloides (Goldfuss) (c) Cyrtoceras sp. undet. (r) 



Pelecypoda Nautilus lawsii Swallow (r) 



Clinopistha? rowleyi Branson (c) Orthoceras atreus Hall (r) 



Goniophora hamiltonensis (Hall ) (r) Orthoceras sp. undet. (r) 



Grammy sia elliptica Hall (r) Orthoceras sp. undet. (r) 



Modiomorpha missouriensis Branson (r) Trilobita 



Nucula cf. lirata (Conrad) (r) Proetus ctassimarginatus Hall (r) 



Nuctda snyderensis Branson (r) Pisces 



Paracyclas elliptica Hall (a) Glyptaspis sp. (r) 



Paracyclas lirata (Conrad) (a) . Ptyctodus calceolus (Newberry and Wor- 



Schizodus chemungensis (Conrad) (a) then) (c) 



Gastropoda Ptyctodus ferox Eastman (r) 



Bellerophon sp. (j) 



Diaphorostoma snyderensis Branson (a) 



The most abundant species are: Athyris fultonensis 

 (Swallow), Lioclema occidens (Hall and Whitfield), Stropheodonta 

 callawayensis (Swallow), Stropheodonta boonensis (Swallow), 

 Stropheodonta equicostata Swallow, Stropheodonta demissa (Con- 

 rad), Schizophoria striatula (Schlotheim), Spirifer euryteines 

 Owen, Stromatopora solidula Hall and Whitfield, Paracyclas 

 elliptica Hall, and Chonophyllum ellipticum Hall and Whitfield. 



Four of the species came up from the Call-away and the 

 others migrated into the Snyder Creek seas or originated there. 

 The fauna is decidedly different from that of the Callaway 

 though the Snyder Creek deposition was continuous with that 

 of the Callaway. Several species, abundant in the Callaway, do 

 not appear in the higher formation. Among these are Acervularia 

 davidsoni Edwards and Haime, Favosites alpenensis Winchell, 

 Cyrtina missouriensis (Swallow), Craenena iowensis (Calvin), 

 and Newberrya missouriensis Swallow. 



Anthozoa. — Two species of corals are abundant. Aulopora 

 repens Knorr and Walch, an abundant form, is widespread in 

 the Hamilton and Upper Devonian of eastern United States 

 and is probably present in the Lime Creek of Iowa. Chonophyllum 

 ellipticum Hall and Whitfield is very abundant. It occurs also 

 in the Cedar Valley formation of Iowa and in the Upper Devonian 

 of the Mackenzie Valley. Ceratopora missouriensis Branson, a 

 rare species, is closely related to Ceratoporas of the eastern 

 Hamilton and Onondaga. 



Stromatoporoidea. — Stromatopora solidula Hall and W 7 hit- 

 field is a very abundant form, which occurs in no other forma- 

 tions save the Lime Creek of Iowa. 



