Reviews: Ramsay—Geology of Great Britain. 61 
as the compact Claystone of the ‘Kreuzbruch’ near Chemnitz. From 
his chemical investigations he deduces the probability of the origin 
of the Felsite-tuff being exclusively derived from the minerals fel- 
spar, quartz, and mica, as they contain all the chemical substances 
necessary to its formation; and he also shows that the composition 
_ of the compact Claystone is so similar to that of the Felsite-tuff, that 
the materials of both appear to be identical, although certain other 
facts, especially the columnar character of the former, show with 
equal clearness that plutonic forces contributed actively to its forma- 
tion, in contradistinction to the purely sedimentary origin of the 
Felsite-tuff. 
The last paper is ‘On the Occurrence of Hatchettine at Wettin,’ 
by Herr Wagner, and relates merely to the occurrence of that mineral, 
in masses which have hitherto been supposed to be Ozokerite, in the 
Royal Coal-mine at Wettin, in association with a notable quantity of 
rock-oil.—H. M. J. 
REVIEWS. 
—_+——__ 
Tue PuysicAL GroLtocy AND GEOGRAPHY OF GREAT BRITAIN. Six 
Lectures to Working Men, delivered in the Royal School of 
Mines in 1863. By A.C. Ramsay, F.R.S., Local Director of the 
Geological Survey of Great Britain. Second Edition. 12mo. 
STANFORD, 1864. 
ROFESSOR RAMSAY’S Lectures make a charming little book, 
written with all the freshness and simplicity of a novice taking 
up the pen for the first time, and contrasting as much with the stilted 
phraseology of the ‘text-book’ writers as the natural voice of a 
singer or preacher refreshes the ear wearied with falsetto. The 
Lecturer is under no such disciplined restraint as Professor Phillips 
imposes upon himself in the work lately noticed, but gives the reins 
to his fancy, and makes a succession of flights at all the great 
speculative questions of the day. 
If the ‘working men’ expected no more than a dissertation on 
Practical Geology, they must have been agreeably surprised to find 
themselves flattered, instead, with an exposition of the most ‘ad- 
vanced’ views of their lecturer. For, while exhibiting in a lively 
and intelligible manner the Geology of this country, of Wales, and 
of Scotland,—the topographical distribution of the strata and their 
various character, with their influence on the scenery, and on the 
occupations of the inhabitants,—he contrives to discuss the origin of 
rocks and rivers, the action of glaciers and atmospheric agencies in 
moulding the surface of the land, the excavation of lake-basins, the 
formation of mineral veins, and many other subjects of equal interest. 
‘Denudation’ very properly forms a prominent topic; denudation in 
all its aspects—by rivers, by rain, by glaciers, by the sea. Every for- 
mation is but so much old material worked up again, with a small 
