64 PLEISTOCENE OF INDIANA AND MICHIGAN. 



a ravine crossing from T. 13 N. into T. 12 N., R. 3 W., abou<t 2 miles east of Cloverdale, near 

 the corner of sees. 33, 34, 3, and 4, shows a buried mucky soil 6 to 8 feet thick, underlain by 

 till that is redder and apparently more weathered than the till above. The buried muck beds 

 are perhaps as conspicuous in these flat areas among the hills of central Indiana as are those 

 found between the Illinoian and Kansan drift sheets of southeastern Iowa, but they are not 

 underlain by the bighly weathered and oxidized till sheet that characterizes the upper part of 

 the Kansan drift in Iowa. The results of the study, therefore, leave the occurrence of a long 

 interval of deglaciation in doubt. 



MINERALS IN THE DRIFT. 



In the absence of other and conclusive evidence of direct invasion the nuggets of native 

 copper in the basal portion of the drift should not be given great weight. It is possible that the 

 copper was transported into districts farther north by ice movement across the Superior region 

 from the Patrician field and was then brought into this region by the Labrador ice sheet from 

 points where it chanced to cross the deposits of the earlier ice sheet. This area in south- 

 central Indiana is in a reentrant angle between the Illinois lobe and the lobe covering eastern 

 Indiana and western Ohio and is likely to have received contributions from both. The path 

 of the Illinois lobe is such as to bring deposits from far north if not from the outcrops of 

 copper -bearing rocks in the eastern end of the Superior basin. So far as this particular area 

 is concerned, therefore, the sufficiency of the evidence of an invasion from the Superior region 

 is doubtful. 



GOLD. 



With the nuggets of copper have been found small amounts of gold, and also a few diamonds 

 and chunks of lead. The copper, diamonds, and lead seem to have been derived from the base 

 of the drift; the gold, however, comes from considerable heights above the base as well as low 

 down, as has been proved by the observations made by R. L. Royse, of Martinsville, Ind., 

 during the sinking of a shaft 5 miles northwest of Martinsville in sec. 24, T. 12 N., R. 1 W., on 

 the slope of a large gravel hill which presumably was formed as a closing feature of the ice 

 occupancy of this region. The shaft was started 65 feet below the highest point of the hill and 

 was sunk to a depth of 135 feet without entering rock. The material was panned for its entire 

 depth and yielded gold at all levels from top to bottom. The following record of the shaft was 

 obtained from Mr. Royse: 



Section of Royse gold shaft, 5 miles northwest of Martinsville, hid. 



Feet. 



1. Gravel and cobble, coarse, with a few bowlders, extending to level of base of gravel hill, 



waterbearing near bottom 32 



2 . Reddish clayey cemented crust with much iron 3 



3. Clay, blue, gummy 6 



4. Sand, coarse, and fine gravel, nearly dry 30 



5. Sand, fine, with but little water 40 



6. Gravel, reddish, with light streaks 14 



7. Clay, deep blue 10 



135 



The "colors" or flakes of gold were most abundant in 1 and 4. The fine sand (5) contained 

 only minute "points" of gold, but the reddish gravel which underlies it showed flakes as coarse 

 as those in 1 and 4. 



diamonds. 



Drift diamonds have been found southeastward from the neighborhood of Minneapolis 

 Minn., across Wisconsin, Michigan, and Indiana into Ohio. Hobbs 1 discussed their distribution 



i Hobbs, W. n., The diamond field of the Great Lakes: Jour. Geology, vol. 7, 1899, pp. 375-388. 



