390 



THE MINERAL REGION OF SOUTH-WEST 



layers of chert above the bed-rock Limestone, marked (d) in the table on 

 page 387, though, as before stated, it is sometimes found as "float mineral"^ 

 in the clay diggings. 



We give below a cut showing a longitudinal section of a run at Swindle 

 Hill diggings, near Joplin, among the most productive of any in the whole 

 region, by an examination of which the disappointed miner can at once see 

 how it ma}^ happen that he may spend his time and money unavailingly, 

 while his nearest neighbor may be very successful. 



1500' 



No. 1 represents the solid or bed-rock limestone, projected to within a few 

 feet of the surface; No. 2, rotten limestone; No. 3, rotten sandy limestone 

 boulders ; No. 4, run of ore, with both Galena and zinc blende among the 

 boulders ; No. 5, broken chert layers, capping the run ; No. 6, loose broken 

 chert; No. 7, clay. This may be regarded as being as nearlj'" a representa- 

 tive or typical lead mine of the Joplin region, as anything that we can give, 

 and the miners of that region will at once recognize it as such, though, of 

 course, mines are different in details. Going westwardly from Joplin, the 

 same general geological formation prevails and the miners at Leadville, Mo., 

 and Short Creek, Kansas, experience much the same difficulties in mining 

 and meet with about the same degree of success. 



We give a sketch of a section of an old shaft at Leadville, which is but 



