SOURCE OF THE OEE. 87 



is only 9f cents. The four samples, 39 to 42, inclusive, are in the broken 

 limestone just below a large ore body, and their average is 19i cents. The 

 samples which are marked on the map with Roman numerals do not show 

 any remarkable changes until No. 13 is reached, which was taken from 

 near No. 42 of the other list. It assayed 65 cents, and an average of nine 

 other samples taken in the drift southeast of this point showed 17i cents. 

 These samples were not far removed from ore bodies. Although the 

 samples in list No. 3, taken in the cross-drift, do not show a uniform increase 

 in metallic contents as the ore is approached, yet they indicate that the 

 rock in the neighborhood of the ore is the richest on the average. The 

 stratified limestone which lies outside the main fissure in this drift averages 

 but 9 cents. The shale is invariably of low grade, the highest assay ob- 

 tained being only 6 cents. 



Results. — From the foregoing facts it will be seen that it is scarcely 

 possible that the ore bodies could have been formed by segregation from 

 the surrounding limestone. Had such been the case all the metals compos- 

 ing the ore bodies would have been found in appreciable quantities in the 

 least changed limestone. The assays prove moreover that the silver in this 

 rock was in all probability an impregnation accompanying the deposition 

 of the ore bodies and was not an original constituent of the limestone. 



segregation from the limestone. — If the ore had been collected in its present 

 position by segregation of any kind, there would have been innumerable 

 places in which minute clusters and bunches would have been formed, and 

 the limestone, instead of being perfectly barren or practically so for great 

 distances in all directions, would have exhibited here and there at least 

 signs of ore. The large caves and pipes are not the only openings to be 

 found in the mass of limestone. There are openings of every size and 

 shape; vuggs, small holes, drusal cavities, open cracks, and fissures are of 

 frequent occurrence throughout the ore-bearing zone as well as in the lime- 

 stone which has not been found to be productive, though the last has not 

 been sufficiently explored to prove that these openings are as common as 

 in the above-mentioned zone. That some of the cavities referred to may 

 have been formed since the deposition of the ore is very possible, but it has 

 been shown already that most of the fissures and cracks were produced 



