FIELD OBSERVATIONS IN NORTHERN NORWAY 7II 
By measurement from the exact geological maps of the field 
we find the areal distribution of the main rock groups to be the 
following: 
km.? 
OuartZ noritern Vom aoe eee 30.0 
Normal monites ec as eeenee $3.2 
35% 35% 
30% 
50% 
25% 25% 
20% 20% 
15% 
10% 
0% 
40% Sid2 50% 60% 70% 75% Side 
Peridorites Norite, Qu norite Granite 
Undifferentiated 
mai gma 
Fic. 3.—Differentiation diagram, based upon the mean composition of the main 
rock groups. ; 
After the modifications necessary for the topographical irregu- 
larities, after recalculation to weight percentage, and after intro- 
ducing the calculated quantity of the granite dikes, the proportion 
becomes the following: Weight 
Percentage 
IADlIGICzeranite scene suey celle sence 3.9 
Owartz noriter ew micn seen Bile 
INormalmoritem sae hea een Bi) adi 
Olivine-bearing rocks.............. 7 
