TERRACES ALONG BIG SIOUX RIVER l3o 



refuse heaps, for even a superficial examination and slight excavation 

 revealed the presence of human bones and teeth, flint implements, broken 

 pottery, the split bones of bison and deer, mussel-shells, and other evi- 

 dences of human agency. Superintendent David H. Boot, of Canton, 

 who made a section of one of these mounds, found skeletons buried in a 

 looser stratum under a surface covering of several* layers of gravel and 

 boulders. Interment took place on the natural surface, and all the ma- 

 terials of which the mound was constructed were evidently carried from 

 a distance. 



Mounds are also common on all the prominent elevations of this region 

 on both sides of the river. 



The Granite terrace extends northward to the State line, where the 

 Sioux quartzite conies to the surface, and southward it is prominent for 2 

 miles below the railway. 



The Klondike terrace occupies a large part of sections 7, 8, 9, 16, 17, 

 and 21, and rises 25 to 40 feet above the river bottom. This is also 

 deeply cut by creeks at both its northern and southern extremities, but 

 the greater part of the plain is quite level, though shallow erosional 

 drainage channels are common. Less distinct terraces also appear at and 

 below Beloit. 



The South Dakota side also presents numerous and extensive terraces, 

 but very frequently these blend with the flat plain, which is here promi- 

 nent, and it is then difficult to determine their limits. They are especially 

 prominent between section 1, township 99 north, range 49 west, and 

 Canton, and again below Fairview. 



North of the Iowa State line the gravel terraces lie on the east side of 

 the river, and are here a continuation of the Granite terrace, but they 

 are interrupted at the state line by exposures of Sioux quartzite and at 

 other points by tributary streams. The terrace opposite East Sioux Falls 

 is prominent for some distance, but its eastern limit was not determined. 



Another prominent bench or terrace is located west of Brandon, within 

 the east lobe of the great bend of the Big Sioux. The Chicago, Minne- 

 apolis, St. Paul and Omaha Eailway follows it for more than 2 miles. 

 The limits of the terrace at Brandon were not determined. 



A narrow terrace also extends along the west side of tlie east bend of 

 the river just below Sioux Falls, and a large terrace island is located on 

 the south side of the river, in part in the northeast portion of Sioux 

 Falls. These terraces will receive further attention. 



So far as could be observed, there were no terraces in the broad valley 

 of the Big Sioux above Sioux Falls. 



