122 The American Geologist. August, 1904. 
olitic rocks, several thousand feet thick, capped by -occasional basalt 
flows. 
The recognition cf Tertiary granitic rocks iii Mexico is entirely 
new. The order of succession of the igneous rocks is: i.Andesyte, the 
oldest; 2. Trachyte; 3, Granitic rocks; 4. Dacyte ;5. Rhyolyte ; 6. 
Basalt. 
Harriman Alaska Expedition, Voltmic IF, Geology and Paleontology. 
B. K. Emerson, Charles Palache, William H. Dall, E. O. Ul- 
RiCH and F. H. Knowlton. New York. Doubleday, Page and 
Company. Roy, Oct., pp. 173, 33 plates. 
Including the Introduction (by Dr. Gilbert) there are eight "parts" 
of this volume, Dr. Palache furnishing three, viz : General Geology, by 
B. K. Emerson, 56 pages ; The Alaska-Treadwell mine, Geology 
about Chicagof Cove, and Minerals, 40 pages, by Charles Palache : 
Neozoic invertebrate fossils, by William H. Dall, 26 pages ; Fossils and 
Age of the Yakutat formation, by E. O. Ulrich, 24 pages ; and Fossil 
Plants from Kukak bay, by F. H. Knowlton, 13 pages. 
The descriptions by Dr. Emerson include such observations on the 
structure as could be made at the various points at which the cruise 
halted, supplemented by later study of the specimens collected, illus- 
trated by figures and plates. The notes on the microscopic thin sections 
are valuable and interesting — especially the metamorphic rock described 
from St. Lawrence island in which the clastic grains of a graywacke are 
intact in a paste of actinolite needles, the actinolite having resulted from 
alteration of the original matrix (p. 40). He found but little evidence 
of rocks older than the Carboniferous, while the Vancouver series of 
G. M. Daw'son, of Triassic, or early Jurassic age, plays a very im- 
portant part in the geology of the coast even to Plover bay in Siberia. 
A variety of igneous rocks, in which granite is common, are associated 
with these sedimentary series. 
Mr. Palache's description of the Treadwell mine supplements that of 
Becker, and is specially full on the new workings opened between 
1895 and 1899. The rock of the country is a black slate. The ore con- 
sists of "a somewhat silicified sodium-syenyte which has been intruded 
as ?. large dike . . . and later charged with gold-bearing pyrite by 
mineralizing solutions." This syenyte is not much altered even where 
gold-bearing. It consists essentially of albite with pegmatitic quartz, 
and orthoclase. The ferromagnesian numerals are lost. The accesso- 
ries are apatite, titanite and sparingly zircon. The secondary products 
are pyrite, abundant in sharp crystals, calcite, sericite, epidote zoisite 
and sagenite groups of rutilc. The walls are uniformly black slate, 
except that in some places a late intrusive, more basic, has entered 
between the syenyte and the black slate. This, when not altered, resem- 
bles gabbro, and so it was named by Becker. The Treadwell Com- 
pany had running 880 stamps, and were crushing of this ore approxi- 
mately four tons per day per stamp. 
Dr. Palache describes in some detail the geology of a small area at 
Chicagof cove which is opposite the Shumagin islands, and gives a 
