ECONOMICAL GEOLOGY. 37 



A shaft at Srnithboro, in Bond county, passed through two 

 of the main coal seams in a depth of 498 feet, and a boring 

 can led down from the bottom of the shaft reported another 

 st-am about forty-five feet below the lower seam in the shaft. 

 The following is a copy in detail of the strata passed through 

 in this shaft : 



Total depth 498 10 



The band of concretionary iron stone in the roof of coal No. 

 r. varies in thickness from six to twelve inches, and if the 

 quantity was sufficient to justify its exploitation, it would be 

 valuable for the production of iron. No. 24 seems to represent 



