FREEBORN COUKTY. 385 



Drift.] 



off the water in the live-foot sand bed. and sixty feet of tine clay, when water rose so copiously 

 from the second saud bed (No. 6 of the first section given) as to compel a cessation of the work. 

 In this shaft were found small pieces of the same coal, all the way. These pieces had sharp cor- 

 ners and fresh surfaces. The total depth here was 106 feet, and the water seems to have been 

 impregnated with the same gas as that which rose in the drill at the point three-fourths of a mile 

 distant. Such water is also found in the well at the ho'el at Freeborn. With sugar of lead it does 

 not present the reactions for sulphuretted hydrogen, and the gas is presumed to be carburetted 

 hydrogen. 



Further exploration was undertaken in 1880. This was done by Mr. E. B. Clark, the shaft 

 going to the depth of 144 feet. The section as reported by Mr. Clark, was found to be soil, 2 feet; 

 yellow till, 14 feet; softer blue till. 29 feet; sand, 1 foot; gray till, harder than the yellow till, 47 feet; 

 saud, 1 foot; gray till, 2 feet; quicksand, 44 feet, "containing at 124 feet from the surface a stratum 

 of slate two inches thick, underlain by six inches of coal''. Small fragments of lignite were found 

 in the blue and gray till, but apparently not larger nor more numerous than are often found in 

 this formation in wells throughout southern and western Minnesota. The remaining four feet 

 were said to have been drilled in "slate"; but nearly all the detritus brought up was gray sand, 

 with which was intermingled a small proportion of black slaty particles, perhaps making up a 

 quarter of one per cent. This boring is eight rods farther east, and at a site three feet lower, than 

 the first of those above mentioned. 



This account of explorations for coal is but a repetition of what has taken place in numer- 

 ous instances in Minnesota. The Cretaceous lignites have deceived a great many, and consider- 

 able expense has been needlessly incurred in fruitless search for good coal. In the early discov- 

 ery of these lignites some exploration and experimentation within the limits of the state were 

 justifiable, but after the tests that have already been made it can pretty confidently be stated that 

 these lignites are at present of no known economical value. This, not in ignorance of the fact that 

 they will burn, or that they contain, in some proportion, all the valuable ingredients that charac- 

 terize coal and carbonaceous shales, but in the light of the competing prices of other fuels, the 

 cost of mining them, and the comparative inferiority of the lignites themselves. 



The drift. Till. This deposit covers the entire county and conceals 

 the rock from sight. It consists of the usual ingredients, but varies with 

 the general character of the surface. In rolling tracts it is very stony and 

 has much more gravel. In flat tracts it is clayey. It everywhere contains 

 a great many boulders, and these are shown abundantly along the beaches 

 of the numerous lakes of the county. The frequency of limestone boulders, 

 and their significance, have already been mentioned. Thousands of bushels 

 of lime have been made from such loose boulder masses, mainly gathered 

 about the shores of the lakes. The two belts of prominently rolling till 

 described on page 877 are parts of a series of terminal moraines that mark 

 the boundary of the ice-sheet in the last glacial epoch.* The average thick- 

 ness of the drift in Freeborn county does not vary much probably from one 

 hundred feet. 



Gravel and sand. In general the drift of Freeborn county is glacier 

 hardpan or till. Yet in some places the upper portion is gravel and sand, 

 showing all the effects of running water in violent currents, such as oblique 

 bedding and sudden transitions from one material to another. 



For a description of the mode of formation of the moraines, see the report of Wuseca county. 

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