406 C. R. Stauffer — The Minnesota Devonian. 



for the whole formation. Thus the lowest beds are full 

 of fossils and the species, the most abundant of which is 

 Productella subalata, belong chiefly to the various genera 

 of Brachiopoda. These beds are succeeded by others 

 which are also quite fossiliferous but the number of 

 species is small and they belong mostly to the Anthozoa. 

 Then comes the most widely varied fauna of all in the 

 beds which have been made the third division of the 

 general section. Although the Brachiopoda are still 

 abundant the conspicuous forms are Gastropoda and the 

 whole fauna differs decidedly from that of both the basal 

 beds and those higher in the section. 



The brecciated beds appear to contain few if any 

 fossils. The fine-grained compact limestone and the 

 associated brown beds are sparingly fossiliferous. The 

 argillaceous limestone beds of the cement quarry near 

 Austin contain fish remains and an occasional Spirifer, 

 while the uppermost portion of the section is again fairly 

 fossiliferous but the number of species is small. These 

 latter are chiefly Athyris fultonensis and Atrypa reticu- 

 laris. The brecciated beds, or the unknown deposits 

 which doubtless occur between the outcrops from which 

 the section herewith was made, may represent important 

 breaks in sedimentation during which marked faunal 

 changes occurred, but the evidence so far obtained is not 

 sufficient to determine that point. It is perhaps signifi- 

 cant that similar faunal changes have been observed in 

 the equivalent beds of Iowa (6). 



The following is a list of the genera and species that 

 have been collected from the Devonian outcrops of 

 Minnesota. 



Fauna of the Minnesota Devonian. 



Dictyonema 2 sp. 



Idiostroma sp. 



Stromatoporella erratica (Hall and Whitfield). 



Acervularia davidsoni Edwards and Haime. 



Cladopora magna Hall and Whitfield. 



Cladopora sp. 



Favosites sp. 



Hederella filif ormis (Billings). 



Zaphrentis sp. 



Crinoid stem. 



