398 C. R. Stauffer — The Minnesota Devonian. 



to the upper shales which are so well developed a short 

 distance to the south of the state line. It seems entirely 

 probable that these upper beds thin out in Iowa before 

 the Minnesota line is reached. The limestones therefore 

 carry the whole of the known Devonian record, as far as 

 Minnesota is directly concerned. These rocks dip gently 

 to the west and south thus bringing in higher beds along 

 a line from northeast to southwest. 



Much of the Devonian is a porous, weathered, impure, 

 buff limestone but it changes rapidly in color and 

 character as it is followed to the southwest. "Where this 

 former character is prevalent it is undoubtedly to be 

 assigned, in large measure, to the leaching and weather- 

 ing of a rock quite different from that which is now 

 exposed. Following the direction of dip there are 

 numerous shades and grades between a porous, abund- 

 antly f ossilif erous buff rock, and a sparingly f ossilif erous 

 blue, or a non-fossiliferous compact gray to white rock. 

 A number of sections were measured for detailed study 

 and others might have been added. A few of them are 

 given herewith to show the Devonian section of the state. 

 They include some of the more important outcrops and 

 give a good idea of the above mentioned variations as 

 well as of the changing character of the fauna which 

 seems to attend it. 



Section along the South Bank of Bear Creek at Hamilton , 

 Fillmore County, Minnesota. 



Pleistocene and Recent. Thickness 



7. Soil and drift 6' 0" 



Devonian (Cedar Valley limestone) 

 6. Limestone, gray to buff, containing the following 

 fauna. 



Athyris fultonensis (Swallow) (c) 



Chonetes scitulus Hall (r) 



Productella subalata Hall (a) 



Schizophoria striatula? (Schlotheim) (r) 



Trochonema sp. (r) 15' 4" 



5. Limestone, gray to buff or brown, massive, abund- 

 antly fossiliferous. 



