BETWEEN WESTON AND MIKE FAULTS. 229 



of White Porphyry that have escaped erosion. Of these the more north- 

 erly one is entirely replaced by iron-stained chert, which forms a rocky 

 outcrop near the crest of the ridge 



On the north slope of the ridge, in the sharp angle formed by the two 

 faults, the Ella Beeler tunnel ran in on granite and struck a coarse quartzite 

 dipping southwest, which forms the base of the Lower Quartzite. 



From Union fault down to the Long and Derry mines the ridge is 

 covered by the upper main body of White Porphyry, in which are included 

 two comparatively thin beds of sandstone and shale belonging to the Weber 

 Shale formation, associated with which are two small bodies of later quartz- 

 porphyry. The dip of these beds is at a low angle to the eastward, the 

 upper being shown by actual outcrops; the lower, which consists of shales 

 with some sandstone, is shown in the Pride of the West (E-15), Camp- 

 bell (E -25 and E-26), Gildersleeve (E-27), and Hoosier shafts on the 

 south slope, and by the Herculaneum (E-14) tunnel on the north slope 

 of the hill. 



The Blue Limestone is proved on the south slope of the hill by the 

 workings of the Aerial Queen (E-34), Homestake (E-36), and other 

 shafts, which have reached it through the overlying White Porphyry, and 

 by the Himalaya (E-35) tunnel ; and on the north slope of the hill by the 

 workings of the Long and Derry group of mines. 



On the steep face of the ridge facing Iowa gulch, above Long and Deny 

 grade, is found one of the few distinct outcrops of the two bodies of lime- 

 stone, the Blue and the White. Here they dip regularly to the eastward 

 at an angle of 10 to 15, and are underlaid by a body of Green Por- 

 phyry. The Belcher 1 tunnel (M-5) runs in on an ore body in the lower 

 part of the Blue Limestone. Above this and a little to the eastward is a 

 prominent black rock-mass resembling at a little distance the outcrop of a 

 body of iron ore. This is the upper portion of the Blue Limestone body, 

 which is here largely replaced by chert and oxides of iron and manganese. 

 Immediately above this and directly under the porphyry is a body of con- 

 glomerate, from 25 to 30 feet thick, which is assumed to be a portion of the 

 Weber Shales cut off from the main body by the porphyry sheet. 



1 Wrongly given lu the Index of Shafts, etc., as Beecher. 



