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POPULAR SCIENCE REVIEW. 
the Colorado range, and of the Elk Mountains, as well as an account of the 
characters, extent, and probable age of the lignitic group, and also an 
interesting chapter on glacial lakes and lake-basins, in which is shown the 
effects of glacial action and other denuding agencies of erosion in giving 
form to the rocky ranges of the West, where in some cases more than 10,000 
feet of sedimentary strata have been swept away at a comparatively modern 
period. Professor Lesquereux contributes an important paper on the 
cretaceous and lignitic floras of North America, with descriptions of some 
new species. There are also reports on the geology of the Elk range, 
Middle Division, San Juan district, and Nebraska, by Messrs. Holmes, 
Peale, Endlich, and Aughey, besides reports on zoology, archaeology, and 
topography. These reports are accompanied by nearly ninety maps, plans, 
sections, and plates, illustrative of the various subjects treated of in this 
volume. 
GEOLOGICAL MANUALS.* 
T HE issue of a second edition of the useful “ Guide to the Geology of 
London and the Neighbourhood,” by Mr. Whitaker, in so short a 
period after the publication of the first, proves that it has been very accept- 
able to a large number of persons who are interested in and anxious to 
acquire a general knowledge of the character and arrangement of the various 
formations which occur in and near the metropolitan area. This new 
edition contains references to the memoirs of geological survey, where 
details of the sections noted may be found. 
The second edition of the u Rudiments of Geology,” by Mr. Sharp, has 
been thoroughly revised, and several important additions have been made 
throughout. The subject-matter is generally clearly and concisely treated, 
and so arranged, together with some tables and woodcuts, as to render it a 
more useful hand-book for the student of the science. 
The little work by Mr. Mello is intended to give a general sketch of the 
geology of Derbyshire. With the exception of some mammalian gravels 
and bone-caves of Pleistocene age, the geology of the county is compara- 
tively simple, consisting of the Trias, Permian, and Carboniferous forma- 
tions; the latter occupy about two-thirds of the whole area. With the 
exception of a small inlying portion of the Leicestershire coal-field in the 
extreme south of the county, the coal measures of Derbyshire, with an area 
of about 230 square miles, are a continuation of the great Yorkshire coal- 
field. It is partly to the underlying millstone grit and mountain limestone, 
aided by denudation, that Derbyshire owes the wild and picturesque fea- 
tures of its dales and the long stretches of moorland, while the wooded and 
more cultivated southern portion occurs upon the softer Triassic strata. 
* ie Guide to the Geology of London and the Neighbourhood.” Second 
edition. By W. "Whitaker, B.A., F.G.S. London : E. Stanford, 1875. 
u Rudiments of Geology.” By S. Sharp, E.S.A., F.G.S. London : E. 
Stanford, 1876. “ Hand-Book to the Geology of Derbyshire.” By the 
Rev. J. M. Mello, M. A., F.G.S. London : Bemrose & Sons. 
