CHEMICAL COMPOSITION IN SEDIMENTS 457 
contact metamorphism were also ruled out as far as possible. In the 
supplementary column the averages are recomputed to the moisture- 
free basis. The close relationship between the slate and _ schist 
averages is at once apparent. A notable feature of both is the dom- 
inance of MgO over CaO and of K,O over Na,O. It is noteworthy 
Sub-Class} Order Rang |Sub-Rang Remarks 
I 2 I 3 2 representatives of this sub-rang in W. T.;* 
I is schistose and not fresh. 
I 2 4 5 No representative of this rang in W. T. 
IL 3 2 3 Tahamose; 29 representatives of this sub- 
2 rang in W. T. 
3 I 3 2 4 Alsbachose; 17 representatives of this sub- 
s rang in W. T. 
o i 3 3 2 8 representatives of this sub-rang.in W. T. 
a I 3 3 4 6 representatives of this sub-rang in W. T. 
a I 3 4 2 2 representatives of this rang and 1 of this 
n sub-rang in W. T. 
3 I 3 4 4 )| No representative of this sub-rang in W. T. 
1S) I 3 4 ne <\\ and only 2 of this rang. 
I 4 2 3 (| Toscanose; 122 representatives of this rang 
IL 4 2 3 abate WAY, ABS 
II 3 2 2 Only 5 representatives of this sub-class and 
1 of this sub-rang in W. T. 
* W. T.=abbreviation for Washington, ‘‘Tables of Chemical Analyses of Igneous Rocks,’ Pro- 
fessional Paper No. 14, U.S. Geol. Survey, 1903. 
Sub-Class} Order Rang |Sub-Rang Remarks 
; : No representative of this order in W. T. 
I 3 2 2 I representative of this sub-rang in W. T. 
I 3 2 3 2 representatives of this sub-rang in W. T. 
: I 
& I 7 i : No representative of this sub-rang in W. T. 
g 4 
A I 4 2 3 
: I 4 2 8 
cS IL 4 2 3 Adamellose; 21 representatives of this sub- 
# I 4 2 3 rang in W. T. 
fe it 4 2 3 
o I 4 2 3 
II 
HI Only 4 representatives of this sub-class in 
Il W. T. and all these are stated to be pos- 
Il sible products of contact metamorphism. 
II 
