THE GEOLOGY OF LIMESTONE MOUNTAIN AND 

 SHERMAN HILL IN HOUGHTON COUNTY, 

 MICHIGAN^ 



E. C. CASE AND W. I. ROBINSON 



University of Michigan 



Limestone Mountain and Sherman Hill consist of three small 

 residual masses of dolomite in southeastern Houghton County, 

 Michigan. The first is partly divided and is locally known as 

 Big and Little Limestone. These paleozoic outliers have been 

 the subject of some previous study, but the visits of the geologists 

 have been brief and the work incomplete. During the summer of 

 19 13 the authors spent six weeks in the region in an attempt to 

 determine the exact age and structure of the beds. The result of 

 this work will be published in full by the Michigan Geological 

 Survey, but the results obtained contain so much of interest that a 

 brief preliminary report seems desirable. 



Limestone Mountain lies half a mile east of the little station 

 of Hazel on the Mass City branch of the Mineral Range Railroad 

 and directly north of the track. Sherman Hill lies one and a half 

 miles northeast of Limestone Mountain. 



The fossils collected were determined by the junior author and 

 finally submitted to Dr. E. O. Ulrich of the United States Geological 

 Survey for revision and for the determination of the exact horizons. 

 For this and for many helpful suggestions we desire at this point to 

 express our thanks to Dr. Ulrich. 



As finally determined, the stratigraphy of the beds is as follows: 



Mid-Devonian. — All that is known of this horizon is a single mass 

 of chert protruding from the talus on the southeastern slope of 

 Big Limestone. It yielded four fossils: 



Chonetes coronatus var. 



Productella cf. navicella and spinulicosta 



Spirifer aflf. pennatus 



Cystodictya cf. hamiltonensis 



^Published by permission of the director of the Michigan Geological Survey. 



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