736 Recent Literature. [ December, 
for I have seldom seen more birds to the acre than during the 
day to which I particularly refer, and never under circumstances 
more likely to result in the disaster of which I speak. 
Usually, a remedy has been or may be provided for any unnec- 
essary or undesirable destruction of birds; but there seems to be 
none in this instance. Since we cannot conveniently abolish the 
telegraph, we must be content with fewer birds. The only moral 
I can discern is that larks must not fly against telegraph wires. 
RECENT LITERATURE. 
POWELL’S EXPLORATION or THE COLORADO River.’ SECOND 
Norice. — Our notice of the second part of this admirable report has 
been long deferred, but the portion on the structural geology of the re- 
gion possesses additional interest on account of the publication of Ma- 
jor Powell’s report on the geology of the Uinta Mountains, among 
which one branch of the Colorado, the Green River, takes its rise. As 
a contribution to the theory of formation of mountains the report is one 
of special interest. The Rocky Mountains, our author shows, have been 
carved out by rains and running water from a great block of sediment 
ary rocks which suffered erosion from the time of its first appearance 
above the sea. The peculiar form of the mountains is due largely to the 
soft nature of the rocks and the dryness of the climate. “Though little 
rain falls, that which does is employed in erosion to an extent difficult to 
appreciate by one who has only studied the action of water in degrading 
the land in a region where grasses, shrubs, and trees bear the brunt of 
the storm. A little shower falls, and the water gathers rapidly into 
streams and plunges headlong down the steep slopes, bearing with it loads 
of sand, and for a few minutes, or a few hours, the district is traversed by 
brooks, and creeks, and rivers of mud..... When a great fold emerges 
from the sea, or rises above its base level of erosion, the axis appears 
above the water (or base level) first, and is immediately attacked by the 
rains, and its sands are borne off to form new deposits.” Thus the 
mountains have never perhaps been higher above the level of the sea 
than at present ; for example. the “ Uinta Mountains were not thrust up 
as peaks, but were carved from a vast, rounded block left by a retiring 
sea, or uplifted from the depths of the ocean, and their present forms a 
due to erosion ! ” 
As to the drainage of this plateau Mr. Powell concludes 
present drainage was established in rocks now carried away from °° i- 
higher regions, but [with remnants] still seen to be turned up agams 
the flanks of most of the ranges.” Thus the present river valleys m 
Exploration of the Colorado River of the West and its Tributaries, Explored. 
1869, 1870, 1871, and 1872, under the Direction of the Secretary of the Smithsonian 
Institution, Washington. 1875. 4to, pp. 291. With Map and Plates. 
“that. the 
