248 Deep Well at Minneopa^ Minn. — Hall. 



^Paper AA^ 



THE DEEP WELL AT MINNEOPA, MINN"ESOTA. — C. W. Hall. 



[The following description is based chiefly on notes and borings secured 

 by Mr. Bruno Bierbauer. The notes were taken on the spot from week to 

 week and the borings were kindly furnished by Mr. Fox, who was in charge 

 of the work. When the depth of 800 feet was reached, Mr. Bierbauer was 

 obliged to leave Mankato. Subsequently Mr. AV. D. Willard tried in vain to 

 obtain further data. All borings which had been saved were so mixed and 

 changed that even the workmen could not distinguish them. So he could 

 learn positively no more than this: — the contract had been fulfilled and the 

 depth of 1,000 feet had been reached. No gas but a good flow of water 

 was secured.] 



During the season of 1888 a deep well was bored at Minneopa, 

 about one-half mile southwest of Minneopa Falls. The purpose of 

 the well was an exploration for natural gas, by some Mankato 

 gentlemen, possibly aided by men and capital from Ohio. The 

 spot selected for the well lies about 100 feet above the level of the 

 Minnesota river, which flows easterly only one mile away. The 

 well is within the Minneopa creek valley and is bounded both east 

 and west by hills 150 to 200 feet above the top of the well. 



After penetrating soil and glacial debris to the depth of 88 

 feet, the Cambrian rocks were entered and were probably not bored 

 through when work ceased at the depth of 1,000 feet. The first 

 of these Cambrian rocks was a white sandstone; this soon gave 

 place to a dolomitic rock which first appeared at 116 feet below the 

 surface. Soon a white calcareous, flinty rock took the place of the 

 dolomite, after which shales and sands alternated until the depth 

 of 585 feet was reached, when a coarse conglomerate of quartzite 

 pebbles appeared. Below this conglomerate, or below 800 feet, 

 the record is uncertain and unsatisfactory. 



In detail, the record of the well is as follows: 



THICKNESS. DEPTH OF WELL. 



1. Soil and clay with evidences of vegetation 10 ft. 10 ft. 



2. Quicksands and gravels 40 ft. 50 ft. 



3. Blue clay with some pebbles 10 ft. 60 ft. 



4. Material chiefly sands of different degrees of coarse- 



ness to the bottom. of the glacial drift 28 ft. 88 ft. 



5. White sandstone. This sandstone in a part of its 



thickness is quite indurated, it effervesces vigor- 

 ously and breaks down into a loose sand when 

 thrown into dilute hydrochloric acid. It is of 

 medium coarseness 28 ft. 116 ft. 



