SNYDER CREEK SHALE. 



45 



Chonophyllum ellipticum Hall and Whit- Pugnoides altus (Calvin) 



field 

 Stromatopora solidula Hall and Whitfield 

 Spirorbis omphaloides (Goldfuss) 

 Lioclema occidens (Hall and Whitfield) 

 Crania famelica Hall and Whitfield 

 Schizophoria striatida (Schlotheim) 



Cranaena calvini (Hall and Whitfield) 



A try pa reticularis (Linnaeus) 



A try pa spinosa Hall 



Paracyclas elliptica Hall 



Ptyctodus calceolus Newberry and Worthen 



The Iowa fauna is characterized by an abundance of signifi- 

 cant spirifers and none of these is in the Snyder Creek shale. 

 The Snyder Creek fauna is peculiar on account of its large variety 

 of stropheodonts, none of the new species of which occurs in the 

 Lime Creek. The Snyder Creek sea and Lime Creek sea were 

 probably contemporaneous but were not directly or continuously 

 connected. 



Eleven of the Snyder Creek species are found in the Mil- 

 waukee formation of Wisconsin. The following are the species 

 as listed by Cleland. 1 



Aulopora repens Knorr and Walch 

 Spirorbis omphaloides (Goldfuss) 

 Atrypa reticularis (Linnaeus) 

 Athyris fultonensis (Swallow) 

 Spirifer euryteincs Owen 

 Spirifer asper Hall 



Schizophoria striatula (Schlotheim) 

 Nucula lirata (Conrad) 

 Paracyclas elliptica Hall 

 Paracyclas lirata (Conrad) 

 Ptyctodus calceolus (Newberry and Wor- 

 then). 



Cleland correlates the Milwaukee formation with the 

 Hamilton of New York. 



The seven Snyder Creek species in the following list are 

 given by Whiteaves from the Devonian of the Mackenzie 

 River. 2 



Atrypa reticularis (Linnaeus) 

 Aulopora repens Knorr and Walch 

 Chonophyllum ellipticum Hall and Witfield 

 Schizodus chemungensis (Conrad) 



Schizophoria striatula (Schlotheim) 

 Spirorbis omphaloides (Goldfuss) 

 Stropheodonta demissa (Conrad) 



Euomphalus inops Hall of the Mackenzie region may be the 

 same as the Snyder Creek Euomphalus hecale Hall. 



Thirteen of the Snyder Creek species are listed by Stauffer, 3 

 from the Hamilton of Ontario, but none of these is significant 

 for correlation purposes. 



Nine of the Snyder Creek species are listed from the Upper 

 Devonian of Maryland 4 , and a larger number occurs in the Upper 

 Devonian of New York but the relationship of the Snyder Creek 



'Wisconsin Geol. Nat. Hist. Surv., Bull. 21, pp. 12-21. 

 'Contributions to Canadian Paleontology, vol. 1, pt. 3, pp. 250-251. 

 •Canada Geol. Surv., Memoir 34, pp. 229-237. 

 •Maryland Geol. Surv., Devonian, Middle and Upper. 



