so zo 



PtPicitncies 



SILICA 



EXCESSES 



Figure 3. — Rock Scries showing Gradations in single Masses 



Broken lines used for calculated data ; full lines for analytical data. Split lines show 

 scattering, but do not in all cases extend to all the points plotted. Small spots show 

 standard rocks, as in figure 1. 



A = Maryland i northeastern part) ; B = Belknap Mountains. New Hampshire; Bb = 

 Brandenberget, Gran. Norway: Bel = Beloeil (Saint Hilaire). Quebec (used data for a 

 single one of the two intrusions) ; Bo = Mount Bohemia. Michigan : C = Castle Moun- 

 tains, Montana : Co = Coryell. British Columbia : D = Saint David*s Head. Wales 

 (author favors heterogeneous intrusion) : E = East Sooke. Vancouver ; Ea = Essex, 

 Massachusetts (alkaline body) ; Es = Essex. Massachusetts (subalkaline body) ; F = 

 Tarrock Fell. England (author favors syntexis) : G = Gowanda, Ontario; Ga = Garabal 

 Hill, Scotland ; II = Haystack Mountain. Montana : HP = Highwood Peak, Montana (a 

 single mass in the Highwood Mountains: see figure 4) : 1 = Ice River. British Columbia; 

 J = Mount Johnson. Quebec: K == Huk. Norway (rough analyses only i : L = Lugar, 

 Scotland (calculated from measured thin sections) ; M = Middle Peak, Montana; Mo = 

 Movie (Purcell), British Columbia (author favors syntexis) ; N = New Jersey (Palisades 

 diabase) ; O = Mount Shefford, Quebec: P = Preston, Connecticut: Q = Square Butte. 

 Montana ; R = Red Hill, New Hampshire ; RL = Rocky Islet. Rainy Lake, Ontario : 

 S = Sudbury, Ontario ; Sh = Shonkin Sag, Montana ; X = Bear Paw Peak, Montana ; 

 Y = Yogo Peak, Montana. 



(626) 



