LE SUEUR COUNTY. (543 



Alluvium. Lake-ridges.] 



nants of which we have here and in the Saint Peter "sand prairie". The length of this ancient 

 channel is three and a half miles, beginning a mile northeast from Ottawa and extending diagon- 

 ally northeast across section 23, and along the east side of sections 14, 11 and 2. For the greater 

 part of its course it is about a fourth of a mile wide, but at its southern end its width is half a 

 mile or more. Its depth is 40 feet below the La Sueur prairie, two to three miles wide at its east 

 side, and the same below the part of this plain, one-fourth to three-fourths of a mile wide, which 

 lies west of this channel, constituting a plateau that reaches from a point one and a half miles 

 northeast of Ottawa to a cemetery situated on its north end about three-quarters of a mile south 

 of Le Sueur. 



Two other terraces of valley drift, or stratified gravel, sand and clay, occur at Le Sueur, 

 intermediate in hight between the Le Sueur prairie and the bottomland. That next to the up- 

 per prairie is at its northwest side, and forms a plain a quarter to a half of a mile wide and two 

 miles long from southwest to northeast, occupying a considerable part of section 2, Le Sueur, the 

 southeast part of section 35, and most of section 36, except its southeast quarter. The east mar- 

 gin of the town of Le Sueur, and Wetter 's brick-yard, are upon this terrace. Its hight is 40 

 feet below the Le Sueur prairie and about 110 feet above the 'river, being on a level with the 

 ancient channel which intersects the higher plain and opens at its north end upon this terrace. 

 The next lower terrace, on which the main street of Le Sueur lies, is from twenty to forty rods 

 wide and about three-quarters of a mile long from south to north. In hight it is 60 to 70 feet 

 below the terrace last described, and it slopes northward from about 50 to 40 feet above the river. 



Alluvium. The bottomland is mostly from 5 to 15 or 20 feet above the river, and is over- 

 flowed by the high water in the spring of nearly every year. The river winds from side to side 

 through this tract of recent alluvium, and in some places directs its current against the higher 

 banks on its border. The width of bottomland on each side of the river thus varies from nothing 

 to a half mile or rarely a mile. Its widest tract seen at any place along the course of the Min- 

 nesota river is in this county, in the three miles northeast from Saint Peter, where its width is 

 about one and a half miles. 



Boulders. Lake-ridges. Boulders of granite, gneiss, schists, and limestone, in size seldom 

 exceeding five feet, occur sparingly in the till of this region on its smooth and gently undulating 

 areas, but are more numerous and in some spots abundant on the hilly and knolly morainic belts. 

 On the shores of lakes they are often seen in unusual numbers, because the waves have washed 

 away the line material of the till, leaving its stones at the base of the eroded bank. Elsewhere, 

 against low shores, these shallow bodies of water have been frozen in winter to their bottom; and' 

 the ice, by the slight expansion of freezing, has in the process of centuries slowly pushed many 

 boulders outward from the lake-bed to its border. In this manner, at the head of lake Elysian, 

 near Okaman, blocks of stone of all sizes up to six feet in diameter have been accumulated in a 

 wall-like ridge four to six feet high and twenty rods or more in length. 



More frequently the ice of the lakes has pushed out and heaped up at their edge a rather 

 broad ridge of gravel and sand, with few or no boulders, having a hight of about five feet above 

 the average level of the lake and often an equal or but little less elevation above the adjoining 

 marsh or lowland, and varying in width from two to six rods. Such ridges were noted at the nortli 

 side of Clear lake in Lexington, and the northwest side of lake Volney in the southeast corner of 

 the same township, the latter extending an eighth of a mile. 



Apiece of copper, weighing about one pound, is reported to have been found in the drift at 

 Ottawa. It was probably brought from the region of lake Superior in the early glacial epoch 

 when the ice covered its greatest area; for the current of the last ice-sheet which overspread this 

 region, forming the terminal moraines, was from the northwest, bringing, as ingredients of its 

 drift, limestone pebbles and boulders, probably many of them from the vicinity of Winnipeg, and 

 rare fragments of lignite and silicified wood, of which the last must be from Dakota. 



Wells in Le Sueur county. 



Examples of the sections of wells in the glacial and modified drift are as follows: 

 Lanesburg. The well at the elevator at New Prague, situated close east of the railroad and 

 south of the main street, which runs on the county line, was bored to a depth of 192 feet. The 

 section was soil and clayey loam, 6; gravel, 4; dark bluish till, 75; fine gravel and quicksand, 4; and 

 again blue till, 103 feet, and extending below. Water, not in large enough amount, was found at 

 10 feet and again in the quicksand at 85 feet, but none below this, and the well is not used. 



