26 ANALYSES OF ROCKS AND MINERALS, 1880-1908. 
¢ I J I. L 
SIO 8 tcearetcraracevaccemuste snione a3 a sshev re oma messes aera eans ie ere Ee ROE SES 47.63 
Al2O3.. 15. 49 
Fe203.. 2.60 
FeO... 8.70 
MBO! co ciaissein 8.40 
CAO oi eeccines 10. 04 
NaO......--- ae i A 3.09 
REO esee ers as ' ‘ 2 H . 36 
H20 at 105°..... as E 35 
H20 above 105°. 1.78 
iO 1.93 
Pa 
~22 
GS case peatdumadelaaeelin oats none 
100. 70 
NEW YORK. 
1, ROCKS OF THE ADIRONDACK REGION. 
Collected by J. F. Kemp, who furnishes the petrographic data. A and G, together 
with the four iron ores, are described by Kemp in 19th Ann., pt. 3, p. 383. Analyses 
A and B by George Steiger, record No. 1715; C to K by W. F. Hillebrand, record Nos. 
1714 and 1717. 
A. Wall rock of iron mine near Lincoln Pond, Elizabethtown. Camptonose. 
Varies from norite to gabbro. Chief minerals, green augite, hypersthene, brown 
hornblende, plagioclase, and magnetite. Microperthitic feldspar less common. 
Garnet varies from absence to abundance. 
B. Coarse gabbro, top of Whiteface Mountain. Hessose. A pyroxenic phase of 
the anorthosite. Contains much labradorite, abundant light-green augite, brown 
hornblende, shreds of more or less bleached brown biotite, and magnetite. 
100.75 | 100.51 
a Mainly present as pyrrhotite. 
C. Pyroxenic anorthosite, Elizabethtown. Hessose. Contains largely labradorite, 
subordinate light-green augite, less brown hornblende, and a little magnetite. 
D. Norite, with close affinity to gabbro. Camptonose. Intrusion in C. Contains 
labradorite, hypersthene, garnets, green augite, brown hornblende, a little brown 
biotite, magnetite, and apatite. 
E. Diabasic norite or gabbro, Elizabethtown. Auwvergnose. Contains the same 
minerals as D. 
