122 The American Geologist. August, 1905 
the overlying Carboniferous limestones. So far as has been 
observed there are no evidences of the existence of clastic 
rocks associated with these gneisses. 
In the Santa Rita mountains, in Grant county, the basal 
crystallines underlying the Paleozoic limestones are com- 
posed chiefly of schists. The exposures are small, and lit- 
tle detailed information on the subject is at present avail- 
able. 
The great Mogollon uplift in western New MJexico ap- 
pears to have an extensive foundation of ancient crystal- 
lines. The region is so covered by late eruptives that most 
of the former exposures are covered up. The same con- 
ditions prevail in the neighboring parts of Arizona. 
Reagan* appears to have found evidences of the presence 
of both Archaean and Proterozoic formations. The rocks 
of Azoic age consist of micaceous, talcose, chloritic, and 
hornblendic schists, and some granites. 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
The Two Islands, and what came oi them. Thomas Condon. 
pp. 211, pis. 30. Portland, Oregon, J. K. Gill Company, 1902, 
$1.50. 
While the author of this volume attempts to supply a popular 
rather than a scientific want, yet the treatment of the geology of 
Oregon is thoroughly scientific. The author is a well known geolo- 
gist who has alone represented Oregon in geological work and 
geological literature for a life-time. In his declining years he has 
gathered together the leading facts, discovered mainly by himself, 
and has in this book preserved them to science, and to the credit 
of his own labors. He has a large collection of Oregon vertebrate 
fossils, and he has supplied others to eastern paleontologists. The 
writer has known of his vigorous activity since the days of his 
earliest geological work. 
The two islands described are named Shoshone and Siskiyou, 
the former in the northeastern part of the state,, in the region of 
the Blue mountains and the latter in the southwestern corner, ex- 
tending into northern California, occupying what is now the Sis- 
* American Geologist, vol. xxxii, pp. 267-308, 1903. 
