BROWN AND REDWOOD COUNTIES. 533 



Modified drift. Alluvium.] 



and southeast of Sleepy Eye, extending from north to south through the S. W. J of section 28, 

 and in the W. J of section 33, in the south part of Home. 



The modified drift which was deposited in the Minnesota valley, as shown on page 581, is 

 represented at New Ulm by the plateau of gravel and sand, a mile long and about an eighth of a 

 mile wide, on which the west and highest part of the city is built (fig. 47). A hollow, about forty 

 feet lower and a quarter of a mile wide, lying between this plateau and the bluff, was formerly a 

 channel of the river, since which time the valley has been cut eighty feet below it. Other re- 

 mains of the valley drift are seen on the southwest side of the river for two or three miles north- 

 west from New Ulm; and on the northeast side it forms long and wide terraces in Courtland, 

 about 150 feet above the river, and a narrow terrace, nearly as high, generally discernible along 

 the bluffs through West Newton township. 



Below the modified drift, New Ulm is underlain by Cretaceous beds which have been al- 

 ready described. These differ in hardness and ability to wii hstand the river's erosion in cutting its 

 valley, which characters have been elements in determining the position and outlines of the lower 

 terraces of this city, as that of Minnesota street, about 90 feet above the river, and that of the 

 depot and brick yard, 50 to 40 feet above the river, and of the continuation of the latter, about 

 40 feet in hight. along the valley some three miles below New Ulm, reaching beyond the Cotton- 

 wood river, as also of a terrace at nearly the same elevation on the opposite side of the Minnesota 

 river. A considerable thickness of modified drift forms the surface of these terraces, including 

 the clay at Aufderheide's brick-yard; but their lower portions are Cretaceous beds, from which 

 pottery clay has been taken near the southeast end of Minnesota street, while the terraces about 

 40 feet high, at each side of the Minnesota river contain beds of nodular gray limestone, much of 

 which has been burned for lime, interstratified with green and red clay and shale. The cut in 

 Cretaceous clays upon Third North street in New Ulm (fig. 46, page 576) is at nearly the same 

 horizon, but in that vicinity it forms no well marked terrace. 



Alluvium. The bottomland at New Ulm and generally along the Minnesota valley at the 

 north side of these counties, is from a half mile to a mile wide. It is composed of recent alluvium, 

 mostly sand and fine silt, having a hight from 5 to 15 feet, and sometimes more, above the river, 

 which meanders through this lowland, here and there sweeping quite to its border. The highest 

 floods, formed by snow-melting in spring or by heavy rains, cover the greater part of this bottom 

 or flood-plain, and at each inundation add slightly to it by their sediment. 



Water-worn boulders. Very remarkable water- worn boulders occur in the Minnesota valley 

 within two miles east from the west line of Redwood county, in sections 17, 18 and 7, Swede's 

 Forest. The river road here winds among outcrops of gneiss and granite, before described, and 

 along their whole extent of one and a half miles in Swede's Forest, detached blocks or boulders 

 of the same formation are seen frequently beside the road and at a distance from it, of all sizes 

 up to fifteen feet in diameter. A large proportion of these boulders, probably a quarter part of 

 all, are very noticeably water-worn, in shallow pot-holes, grooves and indentations, so that some 

 of them, to compare great things with small, have forms like those stamped upon balls of dough 

 or clay by finger-impressions. One of these water-worn boulders, fifteen feet in diameter, lies 

 close beside the road three-quarters of a mile west of the school house which was mentioned on 

 page 569. Again, several large water-worn blocks are seen near together, about twenty-five rods 

 southeast from this school house; one of them, twelve feet long and nine feet high, having its 

 east side remarkably sculptured, like the channel of a water-fall. Boulders water-worn in this 

 peculiar manner are unknown in the ordinary glacial drift, and it appears that these blocks, if not 

 thus worn where they now lie, which seems improbable, were formerly united in a ledge over 

 which the river flowed at some point not far distant to the northwest, probably near the present 

 county line. 



Wells in Brown county. 



Examples of the sections made in the drift by wells in Brown county, are as follows: 



Linden. M. O. Breste; sec. 31 : well, 16 feet; soil, 2; yellow till, spaded, 14 feet; water 

 comes from sandy streaks in the till. 



Milford. William Skinner; sec. 33, at south side of the township: well at house, 30 feet; all 

 yellow till; water seeps, filling the well twelve feet. About eight rods northwest from this, a well 

 50 feet deep was in yellow till for its upper 25 feet, with blue till for all below; scarcely any 



