224 
the larger original maps of Von Buch, Elie de Beaumont, and 
Greenough, by Professor Von Dechen, in one large sheet, published 
at Berlin.* This map exhibits the geological details of a larger 
continuous portion of the surface of the earth than has ever before 
been put together with so much exactness, and set forth on such 
eminent authority. It also presents to the statesman and political 
ceconomist the most important portions of central Europe, under the 
new aspect of the natural divisions of the mineral formations, of which 
each country is composed ; showing that in every region the nature 
and disposition of the substrata lie at the foundation, not only of 
its agricultural productiveness, but also of its capability of supplying 
the materials, which form the basis of its industry and arts. As an 
historical document, this map demonstrates the rapid progress of our 
science, and the state of maturity which it has attained. 
Thus far I have occupied your attention with external matters of 
extraordinary interest in the history of our science, which show 
that geological knowledge is spreading its salutary influence, more 
widely and rapidly than heretofore, over the practical business of 
the country. I now proceed to consider the communications made 
to the meetings of our Society during the past year. 
POSITIVE GEOLOGY.—DEVONIAN SYSTEM. 
In the Home Department of Positive Geology, the most striking 
circumstance has been an announcement by Professor Sedgwick and 
Mr. Murchison of the conclusion to which they were led by Mr. 
Lonsdale’s suggestion in December 1837, founded on the interme- 
diate character of the fossils in the Plymouth and Torbay limestone, 
—that the greater part of the slate rocks of the south of Devon and 
of Cornwall belong to the old red sandstone formation. 
The order of the observations which have led to this important 
result, is nearly as follows :— 
In a paper read at Cambridge, during the winter of 1836-37, 
Professor Sedgwick considered the fossiliferous slates on both sides 
of Cornwall to be of the same formation, and coeval, or nearly so, 
with the calcareous rocks that lie between the slates of South 
Devon. 
* Schropp and Company, 1839. 
