568 



THE POPULAR SCIENCE MONTHLY. 



the most recent of all the gravels of the Del- 

 aware Valley. 2. That the palajoHths found 

 in it really belong to and are a part of the 

 gravel, and that they indicate the existence 

 of man in a rude state at a time when the 

 flooded rivci" flowed on top of this gravel. 

 3. That the data do not necessarily prove, 

 geologically considered, an extreme antiquity 

 of man in Eastern America." 



Prehistoric Mining in North Carolina. 



Mining for mica has become a profitable 

 pursuit in North Carolina. It is a curious 

 fact that the best mines are located upon 

 sites which afford evidence of having been 

 worked in prehistoric times, and are called 

 there "old diggings." Most of the old 

 works probably belonged to the mound- 

 builders, but a tradition coming down from 

 the Indians ascribes some of them to white 

 men. The tradition has recently been con- 

 firmed by the discovery of old implements 

 of iron in a prehistoric shaft in Macon 

 County, which are fully described and fig- 

 ured by Mr. F. W. Simonds, in the " Ameri- 

 can Naturalist." The implements were 

 found in the rubbish which had accumu- 

 lated within the shaft, between thirty-five 

 and fifty feet below the surface, and consist 

 of an axe of a pattern now rarely met with, 

 light in weight, and having on the blade a 

 brand which has been nearly effaced by 

 erosion ; two articles which were evidently 

 gudgeons of a windlass, with heads pronged 

 for the insertion of levers, pointed at the 

 ends, so that they could be driven into a 

 wooden roller, and having the lower part of 

 the shank squared to prevent their turning 

 in the wood, and the upper part round so as 

 to serve as an axle for the roller; and a 

 wedge with battered head. All were of 

 wrought iron, and had probably been worn 

 out and thrown away. Mr. Simonds sug- 

 gests that they are the relics of a party of 

 Spaniards who left one of the ancient colo- 

 nies or expeditions on a " prospecting tour " 

 and tried the mines. Less palpable evi- 

 dences of more skillful mining than that of 

 any aborigines have been found in other 

 shafts. 



The Great Glacier of the Yellowstone. 



Professor Archibald Geikie, Director of 

 the Geological Survey of Scotland, gives in I 



the " American Naturalist " an interesting 

 notice, based on his personal observations, 

 of the ancient glaciers of the Kocky Moun- 

 tains. He refers to the absence of signs of 

 glacial action in the region between the 

 Missouri Valley and the Sierra Nevada, 

 which has been mentioned by American 

 geologists, and regards it as the result 

 chiefly of meteorological conditions. Then, 

 having spoken well of the accounts given 

 of the glaciers of the mountains by our 

 geologists, he records his own observations 

 of them. Entering the Yellowstone Valley 

 from Fort Ellis, a little above the first 

 canon, he observed a prominent rock like a 

 cottage, and weighing more than a hundred 

 and fifty tons, lying, like other smaller errat- 

 ics around it, on crescent-shaped mounds 

 moraine-heaps in the midst of the alluvial 

 plain. The broad valley was full of moraine- 

 stuff. Here, he observes, was a great gla- 

 cier moving northward, "while in British 

 Columbia, on a parallel only about two 

 hundred and fifty miles farther north, there 

 was a massive ice-sheet moving southward. 

 It will be a point of no little interest to 

 trace these two converging ice-streams to- 

 ward each other." In ascending the Yel- 

 lowstone Valley toward the National Park, 

 scattered moraine - mounds and abundant 

 transported blocks continue to denote the 

 course and size of the former glacier. The 

 intense glaciation of the second cafion was 

 a surprise. The rocky knobs at the lower 

 entrance of the great ravine were as per- 

 fectly smooth, polished, and striated as the 

 rocks at the margin of any Swiss or Nor- 

 wegian glacier, and the steep sides of the 

 canon had been ground and striated in the 

 same way, to the height of certainly not less 

 than eight hundred feet. Above the second 

 canon the moraine - heaps become more 

 abundant and tumultuous, here and there 

 inclosing small lakes ; and they were found 

 also, with erratics, in the tributary valley's. 

 The trail from the Mammoth Springs by 

 Blacktail Deer Creek, over to the Yellow- 

 stone, leads across mounds of glacial dihris 

 among which huge bowlders of granite and 

 granitoid gneiss are conspicuous. Some 

 parts of the route present long, smooth 

 slopes, dotted with bowlders precisely like 

 some Scottish bowlder-clay moors. These 

 signs of glaciation can be traced up to and 



