FIG. 334. Glacial map of a portion of the Great Lakes region, showing the ungla- 

 ciated area and the areas of older and newer drift. The driftless area, the mo- 

 raines of the later ice invasion, and the distribution of diamond localities upon 

 the latter are also shown. With the aid of the directions of striae some attempt 

 has been made to indicate the probable tracks of more important diamonds, which 

 tracks converge in the direction of the Labrador peninsula. 



308 



