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lurian divisions made in the slate rocks, by Mr. Murchison, in the 
border districts of England and Wales; and the new distribution 
very recently assigned to the slate rocks of Devonshire and Corn- 
wall. 
A great improvement also has been made by the substitution of an 
entirely new Map of Wales and Siluria, founded on the Ordnance 
surveys of those regions, of which no accurate physical map ex- 
isted at the time of Mr. Greenough’s first publication. Another 
improvement in the execution consists in the union of linear shadows 
with the colours representing the superficial extent of the strata. 
The combined effects of these elements of expression, judiciously 
employed, has been to exhibit, more distinctly, the subdivisions 
of formations, without destroying the unity of the general mass to 
which they belong. By the frequent introduction also of conven- 
tional signs, and figures of reference, Mr. Greenough has produced 
a more condensed assemblage of scientific information, of varied 
kinds, than has been put together in any map of equal extent yet 
published. Extreme attention has also been paid to the physical 
features of the country, and in the orographic details more than 
500 heights are given. The hydrographic features also are deli- 
neated with scrupulous exactness. 
GEOLOGICAL MAP OF IRELAND. 
The last summer has witnessed the production of Mr. Griffith’s 
large and splendid Geological Map of Ireland, containing the results 
of nearly thirty years’ investigation, by that eminent geologist 
and civil engineer. 
Mr. Griffith had supplied an outline of this map published in 
the Report of the Railway Commissioners for Ireland, 1838. It is 
obvious that the information thus conveyed, as to the nature of the 
materials of which the island is composed, affords the most solid 
basis for sound calculation as to the future improvement of Ireland 
by the application of its natural resources. 
GEOLOGICAL MAP OF A LARGE PORTION OF EUROPE. 
During the last year we have also witnessed the publication of 
a beautifully coloured general Geological Map of Germany, France, 
and England, and parts of the adjoining countries, compiled from 
