THE HUMBOLDT ARTESIAN WELL. 75 



east of the river and 5 miles south of the international boundary. The 

 elevation of the surface is 792 feet above the sea, being a few feet above 

 the highest flood stage of the Red River. On account of the saltness of its 

 water, an analysis of which is given in Chapter X, the well is not used. 



Prof N. H. Winchell has reported this section,^ shown by samples from 

 the boring, a summary of which is as follows: 



Section of an arfesinn well, ITumholdt, Minn. 



Feet. 



Soil and very fine sandy flay, .stratified 16 



Moistei and darker, more impervions clay, apparently a downward continuation of 

 the foregoing, but probably including pebbles and bowlders, at lea«t spar- 

 ingly, in its lower j)ortion, being tbere bowlder-clay or till 124 



Pebbly blue till, containing salt water in small quantity at 165 feet below the 



surface 30 



Drift gravel and sand, mainly a gray sand, but containing pebbles up to an inch 

 in diameter, mostly of limestone; supplying an abundant artesian tiow of 

 salt water 10 



Cream-colored magnesian limestone, of grain and texture like the Lower Magne- 

 sian in southeastern Minnesota [and equally like tlie Galena or Upper Mag- 

 nesian and Trenton formation in Manitoba], showing near its base some 

 intermixture of grains of white quartz 295 



Sandstone, composed of rounded quartz grains, reddish in its upper part for 25 

 feet, white in its central part, from both of which the artesian flow of salt 

 water increased, and faintly reddish in its lowest 10 feet 71 



Shales, varying in color from red and brown to gray and green, with occasional 

 siliceous layers that vary from white sand to slightly calcareous, grayish 

 quartzite 93 



Gneiss or granite, composed of opaque gray quartz, flesh-colored orthoclase, also 

 a white feldspar and black mica, "evidently one of the Lauren tian granites 

 as seen at the Lake of the Woods," into which the boring extended 6 



Total 641 



Drift deposits here reach a depth of 180 feet, below which are 458 feet 

 of strata referable to the Trenton, Chazy, and Calciferous series of the 

 Lower Silurian system. 



' Geol. and Nat. Hist. Survey of Minnesota, Thirteenth Annual Report, for 1881, pp. 41-46. 



