MICHIGAN ACADEMY OF SCIENCE. 
39 
within the next four or live years, and that more than seventy per cent 
of the State has been completed already. 
In addition to the co-operative work, the United States Geological 
Survey has completed a map on the field scale of 1:24,000 in the vicinity 
of Calumet, and has extended both vertical and horizontal control across 
the Upper Peninsula in such a manner as to make it possible to in- 
augurate new work without extensive control surveys having to be 
brought into the country before such specific work can begin. 
