Qio THE GEOLOGY OF MINNESOTA. 



(Drift. 



About midway between Preston and Carimona a wash by the roadside revealed loam, 8 feet, 

 underlain by gravelly, red loam 3 feet, with no distinct separation, a few small boulders lying in 

 the water-course below. 



At Carimona a thin layer of drift is usually found under the loam. 

 The same is true at Forestvi.le. 



At Spring Valley the drift is so prevalent that the surface of the country is smooth, and has 

 a lighter-colored soil, with much more clay. There are but few stones or gravelly patches. The 

 loess loam is hardly noticeable. One large boulder lies at the street corner, half a mile south of 

 the corporate limits. 



Between Baldwin's mill, sec. 21, Forestville, and the state line, due south, the country is one 

 of drift prairie, nearly the whole distance, with stones and boulders, some of the latter pretty large. 

 At Etna, sec. 36, Bloomfleld, among a variety of stones pertaining to the drift, may be seen 

 an occasional one that is glaciated. 



At Lime Springs and Foreston, a few miles south of the state line, on the Upper Iowa river, 

 the drift is abundant. 



At Granger there is a light drift, and also where the road turns north to Preston, N. E. J 

 sec. 36, Bristol ; but it becomes lighter still, or entirely invisible, in traveling to Preston. In its 

 place a heavy rich loam, rather clayey, covers the country and smooths it off almost as effectually 

 as if drift-covered. A well, being dug about five miles south of Preston, on the high Trenton 

 area, passes through the loam eighteen feet before striking the rock. 

 The drift is very thin at Lenora, if not entirely wanting. 



About four miles southeast of Preston a large green dioritie boulder may be seen lying in 

 the loess loam, in the road, and a red quartzose pebble. The pebbles that appear in the gullies by 

 the roadside, in the loam area, are generally of chert, from the rock of the locality. It cannot be 

 ascertained whether this dioritie boulder lies on other drift deposits, but it is surrounded laterally 

 only by the loam. 



At Elliota is a thin drift, in the form of pebbles, the largest being three or four inches in 

 diameter. Thence northwestward to Newburgh, nothing but the yellow loam is observable. Be 

 tween Newburgh and Biceford, situated on the western edge of Houston county, no northern drift 

 is visible ; but at Riceford, which lies in a deep and narrow gorge, a few drift pebbles occur iu 

 the street. 



About the center of sec. 29, Holt, is a deposit of gravel. It may be seen in descending the 

 hill northward, just before the road forks to Whalan and Lanesboro. It is considerably cemented 

 by lime, forming a crag, large lumps of which, some eighteen and twenty inches thick, have been 

 used for embankment on the lower side of the road. In some parts it is quite fine, and useful for 

 mortar, for which it has been hauled away. It is at least ten feet thick. 

 There are boulders in the valley of Duxbury creek, sec. 28, Preston. 



Sec. 19, Pilot Mound. In the road going to the river from the south, are a lot of boulders 

 and other drift. The same can be seen on the north side, going up from the ford. The deposit 

 seems to be five or six feet thick, gradually mingling with, and finally becoming replaced by the 

 loess loam. 



Drift gravel and stones are seen along the road in going down the hill to Isinour, from Preston. 

 Drift pebbles and clay occur at the crossing of Watson's creek, on the direct road between 

 Fountain and Preston, and on the terrace of the Shakopee limestone, a quarter of a mile south of 

 the creek. 



Boulders are seen at Spring Valley, and at Mr. Kleckler's farm, two and a half miles east of 

 Spring Valley. 



An occasional boulder is seen in the river valley at Geiner's mill, sec. 31, Jordan; but the 

 most of the surface covering on the rock in the high prairie region, seems to be of the loam. 



East of Highland post office in Holt township, sec. 36, is a conspicuous deposit of drift, 

 exposed in the road, in the form of a stony gravel. It lies on the brow of the Shakopee terrace. 



It is noticeable that in nearly every instance where drift pebbles 

 occur in the region known as driftless, they lie on or are very near an 

 outcrop of firm rock. They frequent the brow of the terrace formed by 



