IGNEOUS AND CRYSTALLINE ROCKS. 49 
C. Light-gray, silvery schist, derived from gabbro. Contains chlorite, calcite, and 
a little quartz, with remnants of feldspar and some leucoxene. Analyses by R. B. 
Riggs, record Nos. 389, 390, 391. Material dried at 105° TiO, undetermined. 
LOWER QUINNESEC FALLS, MENOMINEE RIVER. 
Described by Williams, Bull. 62, pp. 89, 91. 
A. Gabbro-diorite, shore below falls, Wisconsin side. Auvergnose. Contains 
saussurite, hornblende, and ilmenite. Some calcite in the saussurite. Hornblende 
partly altered to chlorite, and ilmenite to leucoxene. 
B. The same, schistose-form. Contains less saussurite. Hornblende and ilmenite 
completely altered into chlorite and leucoxene. Calcite present, and also porphyritic 
feldspar. 
C. Silvery schist, adjoining B, and derived from gabbro. Resembles B in general, 
without the feldspar crystals. Calcite and sericite are present, and rutile in place of 
leucoxene. 
D. Dark massive greenstone. Contains hornblende, chlorite, epidote, quartz, 
leucoxene, with some ilmenite and traces of original feldspar. 
E. Dark schistose greenstone, forming a band in D. Chlorite entirely replaces 
hornblende, and rutile replaces leucoxene. Some feldspar, quartz, and calcite. 
Analyses by R. B. Riggs, record Nos. 384, 385, 386, 387, 388. Material dried at 105°. 
5. 92 6. 28 
2.14 1.96 2.59 
Biri 35 34 +56 
5.05 3. 82 3.99 4.99 
1.82 8. 32 08 5. 38 
99.95 | 99.73 | 100.57 | 100.39 
oa 
UPPER QUINNESEC FALLS, MENOMINEE RIVER. 
Described by Williams, Bull. 62, pp. 104, 113, 114, 121. 
A. Light greenstone. Auvergnose. Contains hornblende, feldspar much altered 
to saussurite, ilmenite with leucoxene border, and some secondary quartz. 
B. Mica diorite porphyry. J. 5.3.4, Mainly andesitic feldspar and biotite, with 
apatite, zircon, sphene, and some calcite. 
C. Biotite gneiss, Michigan side. Contains biotite, soda orthoclase, and quartz. 
Sphene common, zircon and apatite present. 
