Review of Recent Geological Literature. 337 
Roderick Murchison in 1871, he became director general, retain- 
ing the post till 1881. 
To Ramsay geology is indebted for bringing into prominence 
the doctrine of earth sculpture. In his first paper on the denuda- 
tion of South Wales he showed that ‘‘ the existing topography of 
the land has a long and interesting history much of which may 
still be deciphered,” This idea he afterwards enlarged in his 
«« Physical Geology and Geography of Great Britain,” a series of 
lectures delivered at first to working-men. 
Another of his favorite subjects was the erosion of their beds 
by glaciers, and the now familiar doctrine of the excavation of 
the basins in which lie many of the lakes so numerous in glaciated 
regions. This doctrine yet retains some value in special cases, 
but it was doubtless pushed by its able author beyond due bounds. 
He also was among the first to attempt to establish the recurrence 
of glacial episodes in the distant past, as for example, in the 
Permian and Devonian eras and to make prominent the idea of 
paleontological breaks in the record of life, which he did in his 
addresses before the Geological Society of London in 1863 and 
1864, dates which form an epoch in the history of the science, 
In addition to these side issues the results of his direct labors 
may be found in the volumes of the geological survey during his 
directorship. 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
Tenth Annual Report of the United States Geological Survey to the Secre- 
tary of the Interior, 1888-89. By J. W. Powett., Director, Washington, 
1890. Part I. Geology, pp. xv, 774; with 98 plates, and about 70 figures 
in the text. Part II, Irriga‘ion. pp. viii, 1238. 
These volumes were distributed to working geologists and libraries a 
few months ago. During the fiscal year reported, an aggregate area of 
43,222 square miles, including parts of twenty-three states and territo- 
ries, was surveyed and mapped The topographic surveys have been 
extended over the whole of Massachusetts, Rhode Island and New 
Jersey ; more than half of Virginia and West Virginia; approximately 
two-fifths of Missouri, Kansas, and Arizona; a quarter of Maryland and 
Tennessee; and a sixth of North Carolina, Georgia, Alabama, Kentucky, 
and California.. About a tenth part of the national domain has been 
thus accurately surveyed. 
