TWENTY-SETENTH ANNUAL MEETING. 221 



around to the southwest, in the bottom of the Shunganunga valley. It re- 

 appears south of the Shunganunga, at a point two miles southwest from its 

 disappearance. Over that portion of its course the train of boulders, with a 

 large amount of accompanying drift, rests on the naked bed-rock at the 

 bottom of the Shunganunga valley. Its thickness here, wherever it could be 

 seen, by reason of the creek cutting through it, is from four to sixteen feet. 

 It is covered with ten to twenty feet of native prairie earth washin in from 

 the surrounding high lands. The drift debris at the bottom of the valley has 

 considerable clay and small pebbles of various soft rocks, a feature not ob- 

 servable on the surface. Here is an excellent opportunity for studying the 

 character of the original deposit, where it has been buried since its deposit 

 and left undisturbed to the present day. The upper portion of this buried 

 deposit gradually changes in its character to that of native prairie earth, 

 showing that the drift material and the earth from the prairies were being 

 washed down together, at first the former predominating, as the headwaters 

 of the creek are either on the line of the moraine or entirely within the 

 glaciated district; and later the prairie earth predominating, finally being 

 alone, as the drift material became gradually covered up, and was being 

 washed no more. 



Thus there is a bay or sinus opening to the southwest, about two miles 

 deep and two miles wide. Within this embayment stands Burnett's mound, 

 a hill half a mile wide and two miles long, and about 150 feet high, projecting 

 northward from some high lands to the south. Except on the northwest side 

 of the mound, where the moraine approaches to a distance of about one-third 

 of a mile, there is not a sign of any glacial material within half a mile of the 

 hill. North of the line indicated, all over the county, there are to be found 

 on the high lands boulders in plenty, and hidden in occasional hollows beds 

 of drift material that have not yet been washed away. South of that line there 

 is not a particle of boulder clay and not a boulder, save here and there one 

 whose presence there can readily be accounted for. This is also true within 

 that bay; but here there is no exception. There is yet to be found the first 

 sign of glacial material within the bay. 



On the east side of the mound the two miles of the boulder train run 

 along the crest of a native ridge parallel with the hill, with a slight valley in- 

 tervening. On the north and west sides of the mound the moraine is cov- 

 ered up in the Shunganunga valley, as stated. This, Prof. T. C. Chamberlin, 

 of the University of Chicago, says, in the Journal of Geology for November- 

 December, 1894, "affords a criterion of age that is new, so far as we know." 



This conclusion is irresistible: That on the east side, and partly on the 

 other sides, the reflection of the sun's rays from the hill kept the ice from 

 approaching closer; and on the northwest side, where the reflected rays would 

 be the least powerful, the torrent of the Shunganunga creek, passing around 

 the north end of the mound, heavily washed the base of the ice, and aided 

 the sun's rays in keeping the ice from approaching closer.* From the place 

 where the moraine reappears above ground south of the Shunganunga, it 

 continues its general course of north 67 degrees west across the county with 

 very little deviation. Valleys crossing its course do not seem to affect it. 

 It crosses hills and valleys in a straight line, except that in the Mission creek 

 valley the moraine is advanced two miles, making a lobe two miles deep and 

 several miles wide. 



* Later studies of the region show that a swift-flowinpr river, half a mile wide, passed 

 around the mound and flowed southward into the Wakarusa, effectually preveutin;? the ice 

 from reaching the mound, and having more influence in that direction than the sun's rays. 



