REVIEWS 283 
gabbro, diorite, and aplite intrude the sedimentaries. The petrography 
of the igneous rocks is rather detailed for a reconnaissance report. 
Sheared zones occur in the greenstone, and these carry important 
copper values, the only mineral of importance being chalcopyrite. 
Practically no oxidized zones are found. - Auriferous quartz veins also 
occur in the region, and one gold mine is in operation. Ards emikye 
Geology and Mineral Resources of the Solomon and Casadepaga 
Quadrangles, Seward Peninsula, Alaska. By Puivip S. SMITH. 
Bulle 432, 8U.9. sGeol, ‘Survey. ‘1910. “Pp. 234; figs. 26, 
pls. 16. 
This bulletin is the first of a series to describe in detail the geology 
of Seward Peninsula. The results of reconnaissance work for the whole 
peninsula are discussed, to give a general setting, and then the detailed 
geology of these two quadrangles is described. The rocks of the region 
are of sedimentary and igneous origin, practically all of which are highly 
metamorphosed. ‘The metamorphosed sediments consist of the Solomon 
schist (pre-Ordovician [?] ), the Sowik limestone (Ordovician [?] ), 
the Hurrah slate (post-Ordovician [?] ), and the Puckmummie schist 
(post-Ordovician). The metamorphosed igneous rocks are the Casade- 
paga schist, and greenstones. After the intense diastrophic movements 
that affected these rocks, others were deposited and intruded. Of the 
later sediments, but very small amounts of a conglomerate are left, and 
the igneous rocks consist of granitic and basic intrusives, none of which 
cover any considerable area. Unconsolidated deposits of recent age 
are found as stream gravels, high level gravels, and in the coastal plain. 
This region is of economic importance because of its gold production. 
Auriferous quartz veins are numerous, but their values have been such 
that only one mine has ever been on a paying basis. ‘The most important 
veins are largely limited to the Hurrah slate, and the contact of the 
Sowik limestone and the Solomon schist. By far the largest production 
has been from placers in the river gravels, and the locations of the ones 
where the best values are recovered is down stream from the outcrops 
of the Sowik limestone. A few dredges are in operation, and they have 
been very profitable. An ees 
The Copper Handbook, Vol. X, 1910-11. By HORACE J. STEVENS. 
Houghton, Mich., tort. 
As in the past, the work contains condensed information regarding 
all the known copper mines of the world, giving a sketch of the financial 
