1895.] Geology and Paleontology. 741 
plagioclase-augen-gneiss which the author calls a schistose granite-dio- 
rite. Its constituents are quartz, plagioclase, biotite, hornblende and 
orthoclase as its principal components, with garnet, sphene, zircon, 
apatite, muscovite and microcline as the accessories. The quartz is 
penetrated by rutile needles. Nearly all the rock’s constituents show 
evidence of dynamic fracturing. 
GEOLOGY AND PALEONTOLOGY. 
Dawson on the Oscillations ofthe Behring Sea Region.— 
Among the recent contributions to a knowledge of the coasts of Behring 
Sea are the notes made by G. M. Dawson during an extended cruise in 
that region. His paper is supplementary to that of Dall’s relating to the 
American shores and islands of Behring Seas, and gives, generally 
speaking, the general physographie features of the land to which the 
attention of the earlier writer was not directed. We quote the follow- 
ing extracts from his general remarks. 
“ Behring Sea is a dependency of the North Pacific, marked off from 
it by a bordering chain of islands like those which outline Okhotsk 
Sea and the sea of Japan. It differs from these two seas by reason of 
its connection to the north with the Arctic Ocean, and in the fact that 
while the whole eastern part of its extent is comparatively shallow, the 
profounder depths of the north Pacific (in continuation of the Tuscar- 
ora deep) are continued into its western part. The Aleutian Islands, 
regarded as a line of demarkation between the main ocean and Behring 
Sea, are analagous to the Kurile islands with Kamtschatka, and to the 
islands of Japan. As to the Commander Islands, though these appear 
to lie in the continuation of the are formed by the Aleutians, they are 
separated by a wide and, so far as known, very deep stretch of ocean 
from the last of these islands, and it is wholly probable that they may 
represent an altogether independent local elevation analogous to that 
to which Saint Matthew and its adjacent islands are due, 
“The western part of Behring Sea has as yet been very imperfectly 
explored with the deep-sea lead, but the following general facts may be 
gathered from the existing charts: The entire chain of the Aleutian 
Islands is bordered at no great distance to the south by abyssal depths 
of the Pacific. The whole western portion of the chain likewise 
