KEWEENAW POINT. 163 
careful and minute stratigraphical measurement and study. The region 
thus furnishes a type to which the less minutely known occurrences in 
other portions of the Lake Superior basin may be compared, and its name 
has been appropriately given to the series which forms the subject of this 
volume. 
SECTION I—KEWEENAW POINT. 
In the following descriptions of the Keweenaw Point district I draw 
freely, of course, from previous publications, and more especially from 
the reports of R. Pumpelly and A. R. Marvine. My own examinations of 
this district were devoted both to the obtaining a more thorough under- 
standing of the published results of others, and to the study of points left 
obscure by former geologists. 
The accompanying maps and sections (Plates XVII and XVIII) will 
serve to illustrate the main points in the topography and geology of the 
Keweenaw Point district. The topography is from the charts of the United 
States Lake Survey, including a large scale unpublished map for that part 
east of Eagle River. The geology is compiled from Foster and Whitney’s 
map (1850), from a map by W. H. Stevens, 8. P. Hill and C. P. Williams 
(1863), from the maps by R. Pumpelly, A. R. Marvine and L. G. Emerson 
in the atlas of the Geological Survey of Michigan (1873), and from my 
own observations. 
Measured along its middle line from a base line running from the head 
of the Keweenaw Bay at L’Anse N. 60° W. to Fourteen Mile Point on the 
lake coast, Keweenaw Point has a total length of 684 miles to its eastern 
extremity. At its base, on the line just mentioned, the point is 343 
miles in width. From the base the middle line trends N. 32° EK. for 214 
miles to the north side of Portage Lake, where the width is 1935 miles; 
thence it runs N. 40° E. 27 miles to Gratiot bluff—width 124 miles; thence 
N. 63° E. 63 miles to the bluff south of Mosquito Lake—width 64 miles; 
thence due east 10 miles to a point half a mile west of Schlaffer’s Lake— 
width 44 miles; thence S. 56° E. 3 miles to the eastern extremity. This 
