496 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



the outcrop, which crosses Stray Horse gulch just below the tunnel (S-3). 

 Farther south the Agassiz (T-3) finds the vein material and limestone 30 

 feet thick, at a depth of 45 feet, the Goneabroad (T-4) finds it at 80 

 feet, and the Cyclops (T-1), farther east, finds it at 148 feet below rock 

 surface, with a thickness of 50 feet, and passes through it into underlying 

 porphyry. In the Agassiz, as in the Robert Emmet, the vein material is 

 manganiferous iron, with carbonate ore at its upper surface, sometimes five 

 or six feet thick ; about five feet of quartzite are found above the contact, as 

 in Carbonate Hill. The dip is about 30° N. E. The Greenback shaft 

 (0-53) found Lake beds, the northern continuation of the Graham Park 

 area (see Atlas Sheet VI), beneath the Wash. The ore horizon consisted of 

 3 feet of iron and chert, 45 feet of limestone, and again 7 feet of iron. 

 White Porphyry was penetrated 40 feet below this. 



Southeastern rim. — On the eastern rim of the southern end of the basin the 

 outcrops of the Blue Limestone are less continuously proved. The Indiana 

 (P-53) finds limestone directly beneath the Wash, while the Highland Mary 

 (P-52) reaches the lower body of Blue Limestone after passing through 

 122 feet of White Porphyry. The Rarus (P-61) passes through the edge 

 of the Gray Porphyry sheet directly into limestone, showing that here the 

 upper White Porphyry is wanting. It comes in again, however, in the 

 Hunkidori (P-72) shaft, a little east, which penetrated it for 40 feet, after 

 passing through 170 feet of Gray Porphyry and 5 feet of Weber Shales. 



Western rim. — Along the western rim a number of shafts have been sunk 

 in Gray Porphyry, in search of the continuation on the dip of the Lee and 

 May Queen ore body, without having yet reached it, the influx of water 

 making it difficult to sink their shafts. Some had penetrated the White 

 Porphyry a short distance, and these had always found a jiortion of the 

 Weber Shale, either as quartzite or as black carbonaceous shale impregnated 

 with pyrites, at the contact of the two porphyries. All had found Wash 

 from ninety to two hundred feet deep. In the Little Sliver (P-81) the White 

 Porphyry was 41 feet thick ; the Shamus O'Brien (P-73) had penetrated it 

 30 feet ; the Tip Top (P-75), 38 feet ; the Union Emma (P-79), 25 feet : and 

 the Bangkok (P-77), 52 feet; while the Cora Bell (P-78), Forepaugh (P-76), 

 Prince of Orleans (P-71), and Olive Branch (P-70) were still in the Gray 



