178 The American Geologist. 
March 1890. 
different parts of the outcrop at an elevation of 64 feet above 
the foot of the slope, and one from the lowest outcrop gave the 
following percentages of copper : 
Sample No. 1 64 feet level 1.32% Copper. 
" No. 2, lowest outcrop 0.27% " 
" No. 3, 64 feet level 2.88% " 
" No. 4, " " " 3.57% 
Besides this occurrence the writer was also shown other 
specimens of amygdaloidal trap carrying native copper, which 
were said to come from the township of Crooks ; but although 
the locality was carefully examined the deposit could not be 
found as the services of the guide who knew its whereabouts 
could not be secured. Later in the season Mr. Hille, mining 
engineer of Port Arthur, secured the necessary guide and pro- 
ceeded to the place where these specimens were taken, and he 
has since informed the writer that he succeeded in locating a 
dyke-like formation of amygdaloidal trap carrying copper in 
Sec. 4, Con. II of Crooks. But enough has been advanced to 
show that the Animikie rocks of Thunder bay are worth care- 
ful prospecting for copper. 
REVIEW OF RECENT GEOLOGICAL LITERATURE. 
Geology of the quicksilver deposits of the Pacific slope, witli an atlas ^ 
By George F. Becker, pp. xix and 486; with 7 plates, 20 figures in 
the text, and atlas of 14 sheets. (Monographs of the U. S. Geol. 
Survey, vol. XIII, 1888). 
An earlier monograph of this survey by Mr. Becker treats of the 
geology of the Comstock lode and the Washoe district ; and that inves- 
tigation was a most useful preparation for the present work. Steam- 
boat Springs, one of the most instructive localities of quicksilver mining 
described in this volume, is in the west edge of Nevada, only six miles 
northwest from the wonderfully rich Comstock lode, with which it has 
very close relationship in its geology and ore deposits. This locality 
lies close east of the great Sierra, but all the districts in California 
where quicksilver mining has been productive are in or near the Coast 
Ranges, separated from the Sierra Nevada by the Sacramento and 
San Joaquin valley. The comprehensive study of the probable origin 
and manner of formation of these quicksilver deposits has involved 
the consideration of much of the stratigraphic geology of western Cal- 
ifornia, and that of its eastern part, including the Sierra, will doubt- 
less be similarly examined in Mr Becker's next monograph, on the 
Gold Belt of California, which work was entered upon immediately 
after the completion of this report. 
