Review of Recent Geological Literature. 123: 
kiyou mountain region. The author traces the development of these 
islands into Oregon, and notes the changes of animal life as the 
development progresses. These islands each had a nucleus as early 
as the Triassic; they expanded through the Jurassic and had con- 
tinuous increase in area through the Cretaceous. 
The Cretaceous was closed by an important geologic and geo- 
graphic event, the upfold of a colossal sea dyke. This dyHe grew 
into the Cascade and Sierra Nevada range. It separated these 
islands, the Shoshone being enclosed on the east and thence for- 
ward associated with fresh water, and the Siskiyou on the west left 
still subject to marine conditions. This gave the islands different 
life histories, that of the Shoshone being characterized by land 
animals whose remains were washed into the lake in which the 
island stood, and that of the Siskiyou by beautifully preserved 
Eocene marine fossils. The Miocene was introduced by the slow 
initiation of the Coast range uplift, forming finally a Coast range 
valley between the Cascades and the Coast range which is trace- 
able from southern California to Queen Charlotte's sound though 
having different names in its various parts — the San Joaquin, Sac- 
ramento, Willamette, Puget Sound. 
The fresh waters on the east side of the Cascade uplift were 
gradually reduced in area, from lakes connected by streams to 
broad low valleys through which single streams flowed. These in- 
land lakes laid the foundation for the drainage southward of the 
Colorado river, and that northward of the Columbia river. The 
Eocene climate was that of the palm and of the rhinoceros, moist 
and warm. The elevation and continuity of the Cascade range were 
not then sufficient to exclude the warm moist atmosphere of the 
Pacific. Much of the present area of Alaska, as pointed out by the 
author, was yet under the ocean, and there was presented an open 
passage for the Japan current, flowing eastward on its way to the 
Hudson bay and the coast of Greenland, thus "cutting off all accu- 
mulations of ice between Oregon and the Arctic ocean." These 
subtropical conditions were gradually changed to more temperate,- 
and even Arctic, by the increasing elevation of the Cascades and 
the exclusion of the Japan current. This change was accompanied 
by the loss of the rhinoceros and the palm tree, the introduction 
of Miocene animals and plants and finally the Pliocene. 
At the close of the Eocene the Shoshone island was joined to 
the eastern mainland. The larger mammals then swarmed over the 
island. These were Oreodon, Rhinoceros, Entilodon, Bothrolabis, 
various small rodents, cats like the cougar, dogs, diminutive horses 
having three hoofs instead of a single hoof, the composite genus 
Anchitherium 
With the introduction of the Pliocene the Miocene strata were 
slowly and unevenly elevated, the Miocene lakes were drained and 
large quantities of igneous rock were thrust upward through great 
orifices in the strata. The Pliocene lakes were smaller and their 
