U. 8. GEOLOGICAL SURVEY VIEW FROM THE SUMMIT OF GRAVELLY KNOB, NEAR CANNING. portion of Snake Creek. Other streams have cut down according to their size and connection with the James River. The northern end of the lake, as has been stated, abounds in sand, and along the east side. of Sand Lake this has been deeply impregnated with humus, rendering it quite fertile. DRUMLINS. I have found little or nothing which corresponds to drumlins as they are described by several writers. I have not personally studied them in their typical locality, hence can only depend upon descriptions. It is certainly true that none in Dakota resemble closely, either in form or size, those in Massachusetts. The dome-like hills of the Fourth moraine correspond in some features, but they are elongated parallel with the moraine, if at all. Some of them, especially west of Lisbon, are ricklike, with sides steeper than in figures which I have seen, with the exception of those in central New York figured by Professor Davis. These hills are uniformly elongated in the direction of the moraine. Moreover, the dome and rick-like hills are very gravelly upon the surface, although this character may not be true of the main mass. They seem to correspond closely to what Professor Chamberlin would designate as kames in his classification.1 As has been before mentioned, there is a dome-like hill inside of the Second moraine east of Pembroke outlet, which reminded me of descriptions of drumlins. It stands conspicuous upon a nearly level plain. Its form is like a double dome about 25 feet high and 200 feet long. It is elongated nearly north and south parallel with the moraine 2 or 3 miles west. It is surrounded by shallow basins on every side. The clustered hills inside of the Blue Lake loop of the Second moraine in northeastern Logan County seem also to have had a similar origin, though they are less regular in form than the one just described. One visited was about 70 feet in height, roughly circular in outline, and surrounded with basins on the east and south which apparently drained to the southeast. The conspicuous hill west of Redfield, known as Bald Mountain, should be placed in this same class. It is over 200 feet in height above the plain, and may be described as a dome-like mass covered with stony knobs and basins. The knob near Oriska has a similar form. It is possible that the lack of stony material and rocky substrata may partly account for the absence of drumlins in Dakota. OSARS. This term we would use according to the definition given by Professor Chamberlin, to denote gravelly or stony ridges trending with the slope of the surrounding country. In Dakota osars usually lie in the bottom of broad, shallow depressions. One of the finest developments 1 Third Annual Report U. S. Geol. Surv., p. 300. of this class of drift deposits was found northeast of Edgeley, extending from the west 2 miles or more nearly to the edge of the Coteau, and ending upon section 12, T. 134 N., R. 66 W. Its general appearance is well shown in Pl. XIII. Another notable example was found in the northwest corner of Hyde County. It was nearly 2 miles in length and 20 feet in height, of quite uniform development, with sides sloping at an angle of 20 to 25°. It begins near the inner side of the Second moraine near some dome-like hills, and lies in the middle of Hunt's outlet, descending toward the northwest. These may be contrasted in two or three particulars. The first slopes toward the center of the ice sheet and lies far inside the Second moraine. The second lies on the outer slope of the Second moraine and slopes away from the ice sheet. Other cases may be mentioned as follows: South of Driscoll, leading from the south side of the interlobe, there is a winding, stony ridge. extending for a mile or more. Others were found inside the Second moraine, leading toward the outlet a little south of the southeast corner of Kidder County. Others lie less regularly around in a valley just west of the interlobe separating the divisions of Antelope Valley in northeastern McIntosh County. The mounds north of Mound City probably belong to this class. Other examples are found south of Spring Lake outlet on the outer slope of the moraine. The numerous stony ridges trending southwest lining the valley northwest of Swan Lake are to be referred to this same class. Several are found leading over the moraines to the west, north and about Bowdle. None of these were so excavated as to show their internal structure. STRIE. No rocks in this region seem capable of preserving striæ, with the exception of the quartzite layers of the Fox Hills sandstone. These layers are so thin and so easily broken that none were found certainly in position. No striæ, therefore, have been found in the whole region under consideration. It should be added that no bowlders of this formation have been found striated. CHARACTER OF BOWLDERS. Of bowlders little need be said. In Dakota, as usually in the Northwest, they are mainly granites and greenstones from the Laurentian, and fine-grained limestones from the Silurian. No representatives of the red quartzite so common in the valleys south of the ledges at Mitchell and Sioux Falls are found in this region. Small bowlders of the Fox Hills quartzite already described are found quite frequently outside the First moraine, but rarely inside. They are especially abundant in the drift outside the moraine west of the south branch of Beaver Creek in southern Logan County. A few have been found scattered elsewhere, even inside the Second moraine. One specimen was found in northern Hyde County. They are rarely over 6 inches |