246 F 
Part of the finely-ground rock was then treated for nearly 
one hour, with concentrated boiling hydrochloric acid, diluted 
with water, filtered, and the residue washed out; this was 
determined together with what the acid had dissolved, and 
the following results obtained. 
1 2 3. 4, 5. 
Insoluble = 95°79 95°72 89°58 88°69 73:19 
Soluble = 3°39 314 9-18 152 21°26 
Water = 0°82 1:14 1:24 3°79 5°55 
100:00 100:00 100:00 10000 100-00 
SiO; = 0:42 0°30 0°42 0:43 0719 
Al,O; = 0°36 0:12 1:40 trace trace 
Fe.0; a ES 2:01 3°75 0:26 16°47 
CaO = 0°37 0°33 1°68 0:03 0°32 
MgO = 0°43 0°31 Ul 0:21 3°66 
NaO = 0:02 0:37 0°82 0:04 0°12 
Mn.0; = 0°28 
Cr.O3 = 0°62 
CuO = 6°51 
347 3°44 9°38 7°76 21°38 
. From Haverstraw (River Side Quarries) Sp. Gr.=2°608 
. From Newark Quarries, Sp. Gr.=2°589. 
. From Haverstraw (100 feet beneath the Trap rock.) 
Locality not given. Contained apparently Chrysocolla. 
. Shale from Newark Quarries, Sp. Gr. 2°839. 
The specific gravities were determined by Prof. Wurtz. 
oe ww HE 
1. Of red color, yielding a lighter colored powder and very fine 
grained. 
95°79 Insoluble in acid. 
77°28 SiOs (77°70—0°42.) 
18°51 Bases combined with Silica. 
In subtracting the bases dissolved by hydrochloric acid 
from the bases found, we obtain ; 
Al,O; = 11°45. 
CaO = 0:18. 
NaO = 6°87. 
18-50. These two figures agree exactly. 
