Notes OH the Dispersion of Drift Copper. 47 



rock. In Sauk and Chippewa counties, on the same author- 

 ity, specimens have been found. I have picked up two spe- 

 cimens of copper on the shore of Lake Michigan in Ozaukee 

 county, after a severe storm during which they were proba- 

 bly washed from the red clay, which there borders the lake. 

 These specimens were both very irregular, and showed no 

 signs of having been subjected to corrasive action. 



The area over which copper is scattered is thus seen to be 

 very great, perhaps not less than 450,000 square miles. If 

 all the fragments came from Lake Superior, some of them 

 must have been transported about GOO miles to the south, 

 others, 150 or 200 miles, or perhaps more, to the west, and 

 small specimens have been carried more than 100 miles east 

 of the eastern limit of the locality from which the copper 

 is supposed to have come.v There is then an east- west distri- 

 bution, accepting the testimony from Nebraska, of more 

 than 700 miles, and a north-south distribution about 100 

 miles less. 



Farther than the fact of its occurrence, however, little at 

 present can be said of the copper in these various localities. 

 Specimens have been found about Lake Superior and along 

 Lake Michigan, both in Wisconsin and Illinois, in lacustrine 

 deposits. Again, specimens have been found in bowlder 

 clay, in lower and upper drift beds, in beds of streams and 

 in ravines. But the character of the deposits in which the 

 copper has been found, has, in by far the larger number of 

 cases, not been indicated more closely than by the statement 

 that it is drift. Pieces have been found both north and south 

 of the kettle moraine, as well as in it. The general fact that 

 these specimens diminish in size south ward^ seems to be well 

 established, but to this there are some exceptions. Many of 

 the nuggets are Avorn and rounded, but this does not seem 

 to be universal, for angular fragments, and fragments hav- 

 ing the irregular, scraggly form peculiar to this metal, have 

 been found well down in Illinois. What the agency or 

 agencies concerned in this wide spread dispersion is an in- 

 teresting question. If fuller observations had been made, 

 or if those noted had been more exact — e. g., if the precise 

 character of the formations in which the copper occurs had 



