8o POPULAR SCIENCE MONTHLY. 



of each of its parts, to be satisfactorily studied. Recent studies 

 by Canadian geologists have shown that one of the highest sum- 

 mits of the ice cap must have been located some distance west of 

 Hudson Bay, and that another, the one which glaciated the lake 

 region, was in Labrador, to the east of the same body of water. 

 From these points the ice moved in spreading fans both northward 

 toward the Arctic Ocean and southward toward the States, and al- 

 ways approached the margins at the moraines in a direction at right 

 angles to their extent. Thus the rock material transported by the 

 ice was spread out in a great fan, which constantly extended its 

 boundaries as it advanced. 



The evidence from the Oregon, Eagle, and Kohlsville stones, 

 which were located on the moraine of the Green Bay glacier, is 

 that their home, in case they had a common one, is between the 

 northeastern corner of the State of Wisconsin and the eastern sum- 

 mit of the ice mantle — a narrow strip of country of great extent, 



Three Views of a Lead Cast of the Milford Stone (six carats) ; enlarged about three 



diameters. 



We are indebted to the courtesy of Prof. T. II. Norton, of the University of Cincinnati, 



for the above illustrations. 



but yet a first approximation of the greatest value. If we as- 

 sume, further, that the Saukville, Burlington, and Dowagiac stones^ 

 which were found on the moraine of the Lake Michigan glacier, 

 have the same derivation, their common home may confidently be 

 placed as far to the northeast as the wilderness beyond the Great 

 Lakes, since the Green Bay and Lake Michigan glaciers coalesced 

 in that region. The small stones found at Plum Creek, Wisconsin, 

 and the Cincinnati stone, if the locations of their discovery be 

 taken into consideration, still further circumscribe the diamond's 

 home territory, since the lobes of the ice mass which transported 

 them made a complete junction with the Green Bay and Lake 

 Michigan lobes or glaciers considerably farther to the northward 

 than the point of union of the latter glaciers themselves. 



If, therefore, it is assumed that all the stones which have been 

 found have a common origin, the conclusion is inevitable that the 

 ancestral home must be in the wilderness of Canada between the 



