340 
ANALYSES OF BOCKS, U. S. GEOLOGICAL SURVEY. [no. 228 
NEW YORK. 
Roofing slates from Washington County, collected by 
Dale. Of Cambrian age. Described by Dale in 19th Ann. 
A. Red, three-fourths mile south of Hampton Village. 
P>. Empire Red Slate Company, near Granville. 
( J. National Red Slate Company, Granville. 
1). Green, three-fourths mile northwest of Janesville. 
Analyses by W. F. Hillebrand, record No. 1567. 
T. Nelson 
, Part III. 
A. 
B. 
c. 
I). 
Si0 2 
67.61 
13. 20 
5.36 
1.20 
3. 20 
.11 
.67 
4.45 
.45 
2.97 
.56 
.05 
.10 
.04 
none 
.03 
67. 55 
L2.59 
5.61 
1.24 
3.27 
.26 
.61 
4.13 
.40 
3.03 
. 58 
.10 
. 19 
.31 
.11 
.04 
56. 49 
11.59 
3. 48 
1.42 
6.43 
5.11 
.52 
3.77 
.37 
2.82 
.48 
. 09 
.30 
.06 
1.42 
.03 
67. 89 
Al.,0, . - - - - 
11.03 
Fe.,0, 
1.47 
Fe< ) 
3. 81 
Mg< ) - 
4.57 
Ca< ) 
1.43 
Na 2 
.77 
K.,( ) 
2.82 
H 2 at 110° 
.36 
ID ) above 110° 
3. 21 
Ti0 2 - - 
.49 
P 2 £ 
.10 
MnO 
.16 
BaO 
.04 
C0 2 
1.89 
FeS 2 
.04 
100. 00 
100.02 
100. 38 
100. 08 
All contain traces of lithia, of sulphates, and of nickel or cobalt. No carbonaceous 
matter is present. » 
