REVIEWS 293 
the total exhaustion will take place in four hundred years ; and arrives 
at the conclusion that the time may be even less than that given by 
the Commission. That the day of complete depletion will come, the 
author is assured, and when it does come ‘the historian of a powerful 
empire will terminate, very probably, the narrative of a remarkable 
epoch with these words, fnzs Britannae.” W. N. Locayn. 
Cape Nome Gold Region. By FRANK C. SCHRADER and ALFRED 
H. Brooxs. United States Geological Survey, Special 
Report, 56 pp. Washington, 1900. 
The Cape Nome gold field which has recently occasioned so much 
excitement is of special interest geologically on account of being the 
most noteworthy modern beach placers known. The type of ore 
deposits to which these Alaskan beds belong has long been recognized, 
but no bodies of this kind have ever proved so rich. Ancient deposits 
of the same origin are not unknown. Such are the Witwatersrand 
blanket of the Transvaal and the Napoleon Creek conglomeratein Alaska. 
The Nome district is on the southern shore of the Seward peninsula 
in a little known part of northwestern Alaska. ‘The beach rises gradu- 
ally to a sharply cut bench, a hundred to two hundred yards from the 
surf. From the edge of this terrace, which is about twenty feet high, 
the moss-covered tundra extends inland, rising uniformly about two 
hundred feet in four or five miles, when it merges into the highland belt.” 
The bed-rock of the region is composed of limestones and phyllites 
or mica schists interbedded, with some gneiss. Igneous rock is of rare 
occurrence. Over this foundation lie the unconsolidated gravels with 
gold-bearing zones. The authors emphasize the fact that during the 
deposition of the gravels and sands the conditions were not materially 
different from those of today, except that the land stood at a lower 
elevation relatively to the sea. ‘There is no evidence whatever of 
glacial action in the region, and the popular idea that the gravels were 
brought to their present position by ice action is entirely erroneous.” 
The gold-bearing deposits are grouped into gulch-placers, bar- 
placers, beach-placers, tundra-placers, and bench-placers. The gulch 
and beach placers are the most productive. During the past year 
(1899) the production was three million dollars. 
The gold is usually rounded and often smoothly polished. It is 
not evenly distributed through the gravels but gathered in zones. In 
