1885.] Geology and Paleontology. 987 
water increases the tendency to fusion, it is probable that this plas- 
tic zone commences at a depth of about forty miles. The interior 
of the earth may have a rigidity exceeding that of steel, but even 
if, according to the ideas of Wadsworth and some others, the in- 
terior is liquid, this does not affect the action of the surface zone 
nents, while the ultimate crushing produced the mountains. 
Mr. Crosby does not, therefore, believe in the permanency of 
continents, which is held by many geologists as an article of faith. 
We have, he argues, certain knowledge of a Paleozoic subsidence 
of 40,000 feet in the Alleghanies, a Mesozoic subsidence of 50,- 
000 feet in Central Europe, and, according to King, a subsidence 
of 60,000 feet in the Rocky mountains. With these facts in mind 
how can it be held that any part of the floor of the deep sea ever 
has been or will be elevated to form dry land? 
GEOLOGICAL News.—General—All the geological formations 
occurs everywhere on the edges of the older mountain ranges. 
Basalt is rare, the volcanic rocks are mostly trachyte and ande- 
site, and granite covers an area only second to that occupied by 
e Paleozoic formations. Volcanic tuff, consisting principally of 
decomposed silicates, is among the soils of Japan, and forms 
_ Most of the uncultivated plains at the foot of the mountains. The 
geological and topographical survey of Japan has worked over 
an area of about eighty geographical miles square. 
Paleozoic—Mr. O. A. Derby states (Geog. Physica do Brazil, 
Vol. 1) that the Brazilian tablelands are composed of horizontal 
or nearly horizontal beds. The basis of the plateau consists of 
ancient metamorphic rocks; these form nearly the whole of the 
mountain and mountainous tablelands, and appear whenever later 
tocks have been denuded. They thus occur at the bottom of 
nearly all river valleys. The older of these rocks are highly 
Crystalline, the newer less crystalline. The granites, syenite, 
