GRANITE ROCKS OF BUTTE, MONT,, AND VICINITY 743 
summation in the analyses made of each, and the amount of 
material available being exhausted further work could not be 
done. For reference the analyses published by Turner of the 
biotite and amphibole from the quartz-monzonite of the Sierra 
Nevada, are also given.” The close resemblance of the analyses 
of both rocks and minerals to those of the Butte material will 
be noted. 
Biotite Hornblende 
Butte granite 
Butte a Butte ee 
SIO ea erm leeateratcnaee stove aie sars 35-79 25075 45-73 47.49 64.03 
pli Oe Ger eanevate nev taker« cto fisecotens 2551 3.16 1.43 1.21 .60 
le NOG eas cca Steir ROmIneeEre .10 .03 28 .06 .18 
Bree steusa shaper ore slau ey Rndieusts. fe yh) Ly, staves bishus ec svettieits 
Ci ce et npoialersensieciccettnn’s .20 Aree St seco UT Sess 
AUIE Ole tcrettatvovae it stake tells oreisichacs 13.70 14.70 6.77 7.07 15.58 
HO) Mectavcrstertiiacitre evacuate 522 4.65 4.94 4.88 1.96 
Hie Oeeraerteys,, votcacnencutiolee aykcs E2972 14.08 10.30 10.69 2.83 
IMGT OR verexacsveess a aa he eae .19 +45 54 ay Aig 
Bia Ore etic wat hala ce eek weve eace 5g} ene none eats .07 
WTO SvareseQetavaretesatevevoasrsteciisrteens none .12 none ae .04 
CaO rites ccyar erence werent .05 oe], DZS T,02 4.20 
VSO Perret io. dec Soe cay stasayaecaie 125 e377 12532 13.06 2.15 
ARGS OW ersreetsheve, eeuciaeaoateharerd a 9.09 9.19 1.22 -49 4.11 
AN as) eee prada ceu te eececs readies ays 15 fee “yfyf 75) 2.76 
NE UNO) ice Pia kaye wtesigeia acs)vis ohavess tr tr tr aa Pera 
Tel OR below DLOg ea scec ee 120 1.03 -49 oe .20 
He OsvabovesllOr feos aac 3.64 3.64 220 1.86 auf} 
MO talietecscvenete ese cesree Pais 99.59 100.00 98.77 100.03 99.87 
TeessmOsforsH Ga Glee eo 27 12 
99.22 98.65 
Stokes |Hillebrand| Stokes |Hillebrand Stokes 
The Butte analyses are incomplete as the amount of material was too small for 
further work. 
The phosphoric pentoxide (P,O,;) in the analyses of both 
minerals and of the rock itself is assumed to be present as apatite 
and with an appropriate amount of lime is deducted from the 
analyses. The water below 110° C. is assumed to be accidental 
and is also deducted. The analyses are then reduced to 100, 
and the molecular ratios calculated. 
t Some rock forming biotites and amphiboles. A.J. Sci. Vol. VII, 1899, p. 294. 
