554 Geological Society: Anniversary Address, 1843. 
trated work of M. Alcide d’Orbigny, published at the expense of 
the French government, and for which geologists have been long 
waiting with impatience. During eight years of research, this gifted 
naturalist successively examined the coasts of Brazil, the Republic 
of Uruguay, the Argentine Republic from the frontiers of Paraguay 
to Patagonia, the coasts of Chili, Peru and Bolivia ; and by a long 
residence in the last-named country he was enabled to survey, in 
many directions, a large region from the coast to the interior. 
The details of his labours form a first part of the work, illus- 
trated by many sections and by one of most beautifully coloured 
geological maps which ever fell under my observation. In his ge- 
neral observations M. d’Orbigny remarks, that his own observa- 
tions extend from 12° to 42° south latitude, and from 45° to 80° 
longitude west of Paris; a surface comprised between the coast of 
the Atlantic Ocean in Patagonia to Lima on the Pacific; whilst, 
by collecting the observations of other travellers and examining 
fossils from more distant localities, his general views may be said 
to apply to all the vast continent between Colombia on the north 
and the Straits of Magellan! This author reviews in chronological 
order the different rocks, and indicates each change which they 
have undergone, describing the granitic, porphyritic and trachytic 
masses in relation to their extension, composition and elevatory 
agency. He then considers in an ascending order of date the sedi- 
mentary deposits, which he classifies as Gneissie or Primary, Silu- 
rian, Devonian, Triassic, Cretaceous, Tertiary and Diluvial or De- 
trital; showing the dislocations which they have undergone at 
successive epochs, and the causes of these disturbances. 
After an enumeration of all the facts, M. d’Orbigny, under the 
head of conclusions, sketches out all the great revolutions of which 
South America has been the scene; a subject on which he seems 
to display much vigour of thought, but which I cannot now 
attempt to analyse, without doing injustice to him, not having, in 
truth, had time to study his work. One only of his inferences I 
will advert to, as being clearly established by the order of the evi- 
dences ; viz. that, as the increment of fresh matter has successively 
taken place from east to west, so the ancient beds of the sea have 
been heaved up successively on lines trending from north to south, 
and to the west of that primary, or original nucleus on the Bra- 
zilian shores. 
Mr, Murchison next proceeds to the consideration of his subject as relating 
to “ Eastern Countrirs,” inclusive of Hindostan, Affghanistan, China 
and Egypt, terminating the section by the following remarks relative to 
Egypt and Syria. 
After all, it must be allowed that, with the exception of the fossil 
forest, and the recent elevation of her shores which separated the 
Mediterranean from the Red Sea, Egypt presents fewer phzno- 
mena to interest the geologist than any region of similar range over 
which researches have extended; for this mass of land seems to have 
been above the waters during the whole of the ancient periods of 
