ANALYSES OF CHOCOLATE SHALE AND TUFACEOUS SANDSTONE. 155 
Sandstone. 
SiO, 61°65 
Al,O, 13°29 
Fe,0, 2°94 
FeO 6°44 
Cr,0, 0°13 
MnO 0°60 
NiO trace 
CaO .». absent 
CuO a aes 0°01 
PbO A ao ... absent 
ZnO ... absent 
MgO 3°44 
BaO 0°08 
CaO 1°64 
Na,O 2°44 
K,O an aa 0°66 
H,O — (at 110° C.) 1°30 
H;O + (above 110°C.).... 4°02 
CO; 0°90 
TiO, 0°97 
ZrO. 0°01 
ee OE 0°05 
SO, 0°03 
Cl. 0°01 
1 cere wats ee ... absent 
S (FeS,) 0°04 S = FeS, 0°07 
SrO .. absent 
Ei,O .. absent 
Sum .- 100°68 
Less O for Cl 
Specific gravity... 2°693 
Shale. 
38°98 
28°00 
14°39 
0°98 
0°06 
0°04 
0°01 
... absent 
O11 
... absent 
... absent 
0°36 
trace 
0°15 
0°08 
0°18 
3°60 
10°38 
0°22 
2°05 
0°01 
0°06 
0°01 
SONS 
.. absent 
0°09 
.. absent 
.. absent 
99598 
0°04 
0°05 S = FeS, 
Sum... .. 99°87 
2°685 
