WINONA COUNTY. 259 



St. Croix sandstone.] 



between high and low water mark. It is at the same place as the work 

 done here many years ago. Two or three shafts were sunk then on the 

 slope of the bluff, into the shaly and sandy beds of the St. Croix, some hun- 

 dred or more feet above the river. There is a fault in the formation at this 

 place. This has formed a crevice, and has attracted attention. How much 

 the slip is, cannot be stated, nor in which direction, but there is some rea- 

 son for supposing the north wall has passedljelow its former position. The 

 opening of the crevice at the surface is three or four feet wide, some of it 

 being due to erosion by water and frost. The width at fifteen feet below the 

 surface, where this company sunk a shaft, was reduced to about two inches. 

 Drifting alongside of it, twenty-five feet into the bluft, and then penetrating 

 it again, it was found to be made up of a lot of fragments somewhat rece- 

 mented. The downward sections on the different sides of the fault are as 

 follows: 



Section on the south side. 



1. Slope, turfed and wooded, about ' - 20 feet. 



2. Sandrock, - 15 feet. 



3. Shale, green or blue, - - 6 inches. 



4. Fossiliferous Lingula bed, - 6 inches. 



5. Shale, coarse and sandy, - 6 feet. 



6. Slope to the river level, - 15 feet. 



Section on the north side. 



1. Slope, turfed and wooded, 24 feet. 



2. Shale, seen, 6 feet. 



3. Sandrock, - 10 feet. 



4. Fine green shale (or blue) seen, - 6 feet. 



5. Beach to the river level, - 15 feet. 







Above all these rises a high bluff capped with the St. Lawrence, the top 

 being about five hundred feet above the river. 



The galena ore for which this mining was done, occurs on the walls 

 of the fault, accompanied sometimes with pyrite; some of it is found among 

 the debris in the bottom, as it was excavated. It is disseminated in the 

 rock, more or less, on each side of the crevice; particularly is it found in 

 the fossiliferous Lm^Mfa-bearing layer near the bottom of the section on the 

 south side of the crevice. Some of the galena is changed to a carbonate. 

 Galena is also found sparingly in the limerock near the top of the bluff. It 

 is there in seams, and on the faces of the joints, accompanied by calcite 

 coatings. 



