EMIGRANT DIAMONDS IN AMERICA. 3f)3 



Not only did the ice mantle register its advance in the great ridge 

 of morainic material which we know as the "kettle moraine," but it 

 has engraved upon the ledges of rock over which it has ridden, in a 

 simple language of lines and grooves, the direction of its movement, 

 after first having planed away the disintegrated portions of the rock 

 to secure a smooth and lasting surface. As the same ledges have been 

 overridden more than once, and at intervals widely separated, they are 

 often found, palimpsestlike, with recent characters superimposed upon 

 earlier, partly effaced, and nearly illegible ones. Many of the scat- 

 tered leaves of this record have, however, been copied by geologists, 

 and the autobiography of the ice is now read from maps which give 

 the direction of its flow, and allow the motion of the ice as a whole, as 

 well as that of each of its parts, to be satisfactorily studied. Recent 

 studies by Canadian geologists have shown that one of the highest 

 summits 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 alwa} T s 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 constant^ extended its boundaries as it 

 advanced. 



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



rere located on the moraine of the Green Bay glacier, is that their 

 home, in case the} r had a common one, is between the northeastern 

 corner of the State of Wisconsin and the eastern summit of the ice 



lantle — a narrow strip of country of great extent, but yet a first 

 ipproximation of the greatest value. If we assume, further, that the 



mikville, Burlington, and Dowagiac stones, which were found on the 



loraine of the Lake Michigan glacier, have the same derivation, their 

 common home may confident^ 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 points 

 where the several tracks marking their migrations converge upon one 

 another, and the former summit of the ice sheet. The broader the 



