IT. B. Emery — Igneous Geology of Carrizo Mountain. 



Q 15-36 



F. 71-12 



359 



\ 



{ Q 15-36 



! Or -. 17-24 



Al> 



37-20 



Sal. 86-48 



[An 16-68 



fDi... 



I Hy- 



■l lit... 

 |I1 ... 



LAp... 



Rest ... 



4-91 

 2-26 

 3-48 

 1-37 

 •62 



•87 



M 



A. 



7-171 



4-85 \* 

 •62 J 



em. 12-64 



Total. 99-99 



Class I 

 Sal 86-48 ^7 F 

 Fem 



86-48 7 



Q 



Persalane 



Order 4 



71-12 5 7_ 

 15-36^ 3 ^1 

 Britaniiare 



Rang 3 

 K„0 + NaX) 1 102 



Subrang 4 



^5 -^3 



K„O l 



31 



Na,0 7 1 < 5 ^ 7 



Yellowstonose 



CaO' 

 Coloradase 

 Symbols I, 4, 3, 4. 



Melanoeratic types. 



Two types of melanoeratic rocks are present in the dikes and 

 plugs associated with the main intrusions of Carrizo Mountain. 

 In the absence of a chemical analysis it is not thought best to 

 discuss their petrographic character at this time. It may be 

 said, however, that they have been provisionally classified as 

 shonkinite and Carrizo minette, since their mineral character is 

 such as to indicate their relationship to the types shonkinite 

 and minette. Though readily distinguishable under the micro- 

 scope, these rocks cannot be separated megascopically and so 

 for field purposes may be simply classified as " mica trap." 



Leucocratic type. 



Dacite. 



Occurrence. — Dacite was noted in only two places in this 

 region. A dike of it is exposed in Seklagaideza Canyon 

 where the trail to the head of that canyon ascends the east 

 wall, and again on the lower trail from this canyon to Red 

 Rock store. Another and smaller dike, thought to be of the 

 same character, is imperfectly exposed on the east of Carrizo 

 Mountain at the mouth of Chezhindeza Canyon. 



