408 C. JR. Stauffer — The Minnesota Devonian. 



Loxonema sp. 



Murchisonia dovvlingi Whit eaves?. 



Murchisonia sp. 



Pleurotomaria cf . koltubanica Tschernyschew. 



Pleurotomaria sp. 



Raphistoma disciformis Tschernyschew?. 



Raphistoma terrelli Cleland. 



Straparollus clymenoides ? Hall. 



Trochonema monroei Cleland?. 



Trochonema sp. 



Hyolithes alatus Whit eaves?. 



Tentaculites sp. 



Orthoceras sp. 



Poterioceras 2 sp. 



Pliacops sp. 



Proetus sp. 



Fish scales. 



In all the Minnesota Devonian is known to contain sev- 

 enty-seven species and some of them are probably new. 

 The formation continues southward into Iowa where it is 

 said to have a much larger fanna. It is apparently the 

 equivalent of the Cedar Valley limestone of Iowa and this 

 is a satisfactory formational name in Minnesota because 

 much of it is found outcropping in the valley of Cedar 

 River and its tributaries. It is possible, however, that the 

 limits of the Cedar Valley limestone of Minnesota do not 

 correspond exactly to those of the same formation in Iowa 

 if the entire Minnesota Devonian is included in that 

 formation. 



The Devonian of Manitoba and the Mackenzie valley 

 carry a few of the same fossil forms that are common in 

 the Cedar Valley limestone of Minnesota. Unfortunately 

 the fauna of that northern region is not as well known as 

 might be desired. Whiteaves studies (7) have given a 

 very good idea of several divisions especially that of the 

 String ocephalus zone in Manitoba and a fair knowledge 

 of the same zone at the "Ramparts" on the Mackenzie 

 River (8). Although the finding of two drift specimens 

 of String ocephalus burtini has been reported in Minne- 

 sota (9) the species is not known in the Devonian lime- 

 stones of this state. In fact the Cedar Valley limestone 

 fauna of Minnesota has nothing in common with the 

 String ochalus zone except certain long range species that 

 are likely to be found in the Middle Devonian of most any 



