REVIEWS 191 
Mississippi. It is admirably adapted to the needs of teachers and 
could well be made the basis of a practical and interesting first course 
in geology. 
Mississippi is particularly fortunate in the publication of a report 
such as Mr. Lowe has prepared. It deserves a wide circulation among 
the people of that state. 
eke 5: 
Geology and Ore Deposits of the Philipsburg Quadrangle, Montana. 
By. W. H. Emmons and F. C. Carxins. U.S. Geol. Survey, 
Prot Paper! 7o. Tons.) EPpy 277i. spise 17, gs. 55: 
The Philipsburg quadrangle includes an area of 827 square miles 
lying immediately west and northwest of Anaconda, Montana. It is a 
country of strong relief, almost midway between the eastern and west- 
ern divisions of the Rocky Mountains. The geologic section includes 
formations ranging in age from Algonkian to Recent. The Belt series, 
the oldest rocks in the area, is divided on lithologic grounds into six 
formations. Their total thickness is 15,000 feet. Next above and 
separated from the Belt series by a striking unconformity is the Cambrian 
system, comprising the Flathead, Silver Hill, Hasmark, and Red Lion 
formations. The Red Lion contains Upper Cambrian fossils. It is 
overlain by the Maywood formation, of doubtful Silurian age. The 
Devonian is represented only by the Jefferson limestone; the Missis- 
sippian by the Madison limestone; the Pennsylvanian by the Quadrant 
formation. Though the stratigraphic relations of the Paleozoic sys- 
tems was not clearly made out, each is probably set off by disconformities. 
The Mesozoic is not strongly developed in this part of Montana. 
Only three formations are here present—the Ellis, Kootenai, and 
Colorado. The early Tertiary was marked by powerful crustal move- 
ments. The pre-Tertiary sediments were complexly folded and over- 
thrust and extensive igneous masses were intruded. Later the region 
was the scene of two epochs of vulcanism. Certain gravel deposits 
contain Miocene vertebrates. The Tertiary closed with tilting and a 
general uplift. During Pleistocene time there were at least two stages 
of Alpine glaciation. 
The early Tertiary batholiths and smaller intrusives are granites, 
granodiorites, and diorites, with associated pegmatites, aplites, and 
lamprophyres. At and near their contacts with these intrusives the 
sediments are notably altered. The pneumatolytic solutions that 
effected these changes are believed to have carried chlorine, fluorine, 
