THE MINERAL DEPTHS 



oil. He backed up his assertion by offering to stake 

 his experience against the capital of a company which 

 was formed at his suggestion. Before any wells were 

 actually started, however, a prudent member of the 

 company consulted the State geologist on the subject, 

 receiving the assurance that no oil would be found 

 in the neighborhood. Strangely enough the word of 

 the man of science triumphed over that of the "oil 

 expert," and although some tentative borings were 

 made on a minor scale, no great amount of money 

 was sunk. It developed afterwards that the evidences 

 of oil found from time to time had been the secret 

 \w,rk of the "expert." 



In general, prospecting for oil differs pretty radically 

 from prospecting for most other minerals. A very com- 

 mon way of locating an ore-mine is by the nature of 

 the out-crop, that is, the broken edges of strata of 

 rocks protruding from hillsides, or tilted at an angle 

 on level areas. If the ore-bearing vein is harder than 

 the surrounding strata it will be found as a jutting 

 edge, protruding beyond the surface of the other lay- 

 ers of rocks which, being softer, are more easily worn 

 away. On the other hand, if this stratum is soft or 

 decomposable it will show as a depression, or "sag" 

 as it is called. Of course such protrusions and de- 

 pressions may only be seen and examined where the 

 rocks themselves are exposed; vegetation, drift, and 

 snow preventing such observations. But the vegeta- 

 tion may in itself serve as a guide to the experienced 

 prospector in determining the location of a mine, 

 peculiar mineral conditions being conducive to the 



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