s 
174 ANALYSES OF ROCKS AND MINERALS, 1880-1908. 
3. MISCELLANEOUS ROCKS. 
A. Minette. Dike, west bank of Columbia River, 1 mile above Northport. SR. 
2 of wyomingase. Collected by F. L. Ransome, who furnishes the petrographic 
description. Analysis by W. F. Hillebrand, record No. 1988. Contains orthoclase, 
possibly some plagioclase, abundant biotite, pyroxene, apatite, and titanite. 
B. Brucite-serpentine rock, from quarry of the United States Marble Company, 
12 miles north and west of Valley, Stevens County. Resembles ordinary serpentine, 
but contains also brucite, chlorite, and hydro-magnesite. The brucite amounts to 
about 60 per cent. Described by Clarke in Am. Jour. Sci., 4th ser., vol. 15, p. 397. 
Analysis by George Steiger, record No. 2009. P. R. C, 340. 
C. Matrix of dumortierite, north fork of Washougal River, Skamania County. 
Analyzed and described by W.T. Schaller, Bull. 262, p. 105. Contains andalusite, 
quartz, muscovite, a little dumortierite, and accessory pyrite, magnetite, possibly 
ilmenite, leucoxene, and apatite. <A little B,O, present, undetermined. 
A B. Cc. 
BIOs sco since ecseaties cota einyeekeEseees Sey senor emece user te esaeeg eter ese 41.57 | 13.08 57.18 
AhbOs 9.75 1.63 34.10 
Fe.03 4.06 1.25 54 
FeO. 4. 47 +19 28 
MgO 8.65 | 56.44 10 
CaO. 11.10 33 63 
NGpO wa scenes nensaieee cece arene smnded £555 DE cheer anes ed Ma cememchea wae seine 1.57 | none 39 
Ke 
H20 at 105°...... 
H20 above 105° 
TiO. 
ALASKA. 
1. DOUGLAS ISLAND. 
A. Diorite, Treadwell mine, Douglas Island. TYuolumnose. Contains plagioclase, 
mostly albite, with secondary quartz, calcite, and pyrite, the latter apparently replac- 
ing ferromagnesian silicates. Described by G. F. Becker in 18th Ann., pt. 3, p. 7. 
Analysis by W. F. Hillebrand, record No. 1585. 
B. Albite diorite, Treadwell mine. Contains plagioclase, a little microperthite, 
hornblende, epidote, calcite, and pyrite. ; 
C. Albite diorite, Treadwell mine. Like B, but with sericite, more microperthite, 
and no hornblende. 
D. Altered diorite. Contains calcite, biotite, chlorite, quartz, and pyrrhotite. 
E. Amphibolite. 
Rocks B to E described by A. C. Spencer, in Bull. 287. Analyses by G. Steiger, 
record No. 2168. 
