PETROGRAPHY OF SOME ROCKS FROM THE
SOUTH ORKNEY ISLANDS AND THE
DuNcaN Srowlnt, Jr.. Michigan State College, East Lansing, Michigan.
Introduc tion and acknowledgments
South Orkney Islands..
Snow Hill Island..
James Ross Island
Hope Bay, Louis Philippe Land
The age of the intrusives.
fNrnooucrroN AND AcrNowr-BtcMENTS
There are 294 specimens of Antarctic rocks and minerals in the col-
lections of the University of Michigan. By the Spring of 1935, 178 speci
mens from six of the eight Antarctic expeditions represented, had been
studied petrographically and the results published. There remained 116
rocks and minerals, collected by the Scottish National Antarctic, 1902-
1904, and the Swedish Antarctic, 1901-1903, Expeditions to be examined
microscopically. A project grant from The Geological Society of America
and a grant-in-aid from the Society of the Sigma Xi have made this
research possible. Grateful acknowledgments are due to Professors
Laurence M. Gould, William H. Hobbs, Walter F. Hunt, and Chester B.
Slawson, and Mr. W. L. G. Joerg for their interest shown in this in-
Dr. R. N. Rudmose Brown, of the University, Sheffield, England,
furnished, through exchangeof materialwith the University, nine duplicate
specimens obtained from the South Orkney fslands by the Scottish Ex-
pedition. Dr. Gregori Aminofi, of the Mineralogical Department, Riks-
museet, Sweden, contributed, also through exchange, 107 duplicate
specimens collected from the Antarctic Archipelago by the Swedish
Figure 1 is a sketch map of Antarctica showing the location of the
South Orkney Islands and the Antarctic Archipelago. Figures 2 and 3
are sketch maps of the South Orkney Islands, and of the northern region
of the Antarctic Archipelago.
JOURNAL MINERALOGICAL SOCIETY OF AMERIEA
Frc. 1. Sketch map of Antarctica showing locations where specimens were co