590 GEOLOGY AND MIKli^G DTDCSTEY OF LEADVILLE. 



Table II. — Silica and allcali determinations. 



Variety. 



Si02 



85a 

 109a 



269a 

 269a 



Porphyry 



.. do.... 

 ....do.... 



...do.... 

 Ebyolito . 



do. 



MoimtZlon. 

 White 



...do 



.. do 



Gray 



Pyritiferoud . 



Green 



...do 



Mosquito . 



.do Silvoiheels 



Porphyrite . 



Hornblende and 



biotite. 

 Hoiiiblende 



Little Han-y shaft, Prospect Mountain 



Quarry, California galth ! 



Above Blue Limestone, Dyer Mount- 



Summit of Mount Lincoln 



Dike in eastern spur of Mount Lincoln 



El Paso mine, Clinton gulch 



Near Onota Claim, Johnson gulch 



White's gulch 



South head of Mosquito gulch 



Between Buckskin and Mosquito 



gulclies. 



North Mosquito amphitheater 



North face of Mount Lincoln 



North of East LeadTille 



Summit of eastern spur of Mount Sil- 



verheels. 



Mount Silverheels 



South wall of Buckskin gulch 



Arkansas amphitheater 



Ten-Mile amphitheater 



73. 50 



TO. 74 I 



66.45 

 64. IG 

 69.00 

 68.10 



65.05 

 63.85 



North Mosquito amphitheater 54. 54 



Biotite . 

 ...do.. 



Buckskin amphitheater 



North Mosquito amphilbeater. 

 Arkansas ampuitheater 



.do 



.. do I Liparite. 



Showing quartz 



Compact 



Tufa 



65.08 < 

 60.42 



56.62 

 57.33 

 57.76 



65.73 

 64.80 

 60.29 

 59.20 

 71.44 

 74,45 

 69.54 

 68.05 

 76.84 

 65.75 



Trachyte. ... Quartziferous 

 Andeaite Hornblende — 



. -. do j Dacite 



... do Hypersthene.. 



-do. 



.do . 



Chalk Mountain, eastern edge 



Northeast point of Chalk Mountain . . 



Southern cud of Black Hill 



South bank of Empire gulch 



Near Granite. Chatfee County 



Little Ellen s'.iaft. McNulty gulch . . . 



do i 05.21 



Five miles below Salt Works, South I 70. 30 

 Park. 



Head ofLittle Union gulch 01.22 



Buffalo Peaks, northwest Peak 57. 60 



Buffalo Peaks, central amphitheater.. 66. 50 



Buffalo Peaks, northeast spur 56. 19 



Buffalo Peaks, base of middle peak i 60. 36 



3.5G 

 2.59 



2.93 

 4. 62 



2.70 

 1.97 



3.46 

 2.29 



3.91 

 3.15 



3.45 

 2.91 



4.26 

 3.55 



4.08 

 3.50 



3.87 

 2.96 



None 

 None 



oComplcte analysis in Table I. 

 Note.— Blanks in the above table denote simply that ; 



b Analyzed by L. G. Eakins. 

 » tests were made for the substance indicated. 



