550 W.CROSS, J. P. IDDINGS, L. V. PIRSSON, H.S. WASHINGTON 
A A 
[o/e) [oe] 
I 
15.00 
1, 9.66 
7.00 7.00 
t2 5-40 
4-33 
2 3.00 3.00 
2.20 
, 
2 I.Q1 
1.66 1.66 
6) 1.46 
1.29 
3 1.00 1.00 
0.78 
3 0.68 
0.60 0.60 
A 0.52 
0.45 
4 2.33 0.33 
0.23 
4’ 0.18 
0.14 0.14 
as 0.10 
0.06 
5 ©.00 0,00 
B B 
Fic. 1.—Limiting Ratios for Fic. 2.—Limiting Ratios for 
Intermediate Magmas. Transitional Magmas. 
