66 SKOLU: 
the rock from the Oki Islands differs from the others in lower 
silica and in total and relative amounts of iron oxides. 
* Loss on ignition. 
A. Comendite from Iibi, Dégo, Oki. K. Yokoyama analyst. 
B. Comendite from Comende, Sardinia. M. Dittrich analyst. 
C. Comendite from Iskagan Bay, East Siberia. 
_ Norms of these rocks are given in the following table: 
Quartze cists ciate et tes, tei in ee caterers carers 
Dropsidenys ocean ids stpaciage ouslalaeta eta 
Hiyperstheneseesn en heater 
IMaenetite seers nadccsie ne cin memerticecatrat 
lie ma titer ees eo sina. eee neta aerate tac ee ieee 
Plmenite esse teat eee Pe ae ree ae ee 
AD AtITO NS SCs eS tak ie crete Ve ale rai sent cet 
A B Cc 
PBL 74.76 75-44 
II.20 I1.60 Ir.098 
2) Ds, 3.50 0.88 
2.66 0.19 I.02 
0.08 0.18 0.10 
0.27 0.07 0.33 
4.29 4-35 4.06 
4.81 4.92 5.01 
I.45 0.64 0.68 
Senn Behe 0.13 
0.44 Trace Trace 
0.10 Trace os 
0.10 Trace Trace 
99.89 100. 21 99.63 
H. S. Washington, analyst. 
A B Cc 
28.3 31.6 31.9 
28.4 28.9 30.0 
30.9 32.0 Beno 
4.6 4.2 0.9 
0.5 be Anes 
3.4 0.5 Bit 
0.9 0.7 0.9 
alae 1.6 ve 
0.9 Bet 
0.3 
From the above table, it will be seen that the rock from the Oki 
Islands is closer to that of Comende than that of Iskagan Bay and 
is richer in femic minerals than the other two. 
The ratios of the Oki rock are as follows: 
Sal 
Fem 
Q 
= 
