146 PROCEEDINGS OF THE GEOLOGICAL SociEeTy. ([Dec. I, 
These objects have already been zealously followed by the geolo- 
gists of the United States; but it appears, that from a want of 
European specimens, they have usually been obliged to limit their 
comparison of species to the figures given in our geological works, 
which I need hardly state are seldom sufficient to afford paleeonto- 
logists in a distant country much certainty of the identity of their 
species with ours. It is only by the comparison of specimens that 
we can hope to arrive at any certain conclusions ; and we have never 
yet had so good an opportunity of making this desirable comparison 
as has now been offered by Mr. Lyell, who has brought together an 
extensive collection of specimens from nearly all the paleeozoic for- 
mations of the United States and Canada. 
My examination has been confined to the fossil Mollusca; Mr. 
Charles Bunbury has already favoured the Society with reports on 
the fossil plants collected by Mr. Lyell; and the corals and crinoidea 
have been placed by Mr. Lyell im the hands of other naturalists, 
from whom we may expect full information concerning them. The 
only part of this valuable collection still unexamined, is that contain- 
ing the Trilobites and other crustacea. 
Throughout my examination I have never hesitated in correcting 
what appeared an erroneous name or reference given by any of our 
American colleagues; but I trust that they will not impute this 
course to any want of respect for their labours, from which I have 
derived constant assistance: having specimens from the two coun- 
tries before me, and knowing from their works that most of their 
comparisons were only of specimens against figures and descriptions, 
I adopted the conclusions which appeared drawn from the better 
evidence. I have been constantly assisted by our colleague Mr. 
Morris, and all points of difficulty, or of any peculiar interest, have 
been submitted to him. I cannot sufficiently thank him for the 
help he has given me, without which I should not have thought my- 
self equal to so extensive a task. 
Mr. Lyell’s collection is very extensive and in excellent working 
order; the part examined contains nearly 200 species of Mollusca 
from formations ranging from the lowest fossiliferous beds to the top 
of the Devonian series. In general the specimens are in better con- 
dition than those we find in similar formations here; the Lower 
Silurian series in particular affords specimens in a condition far supe- 
rior to what we are used to. The shells are rarely distorted, and 
most of the rocks appear both free from slaty cleavage and unaltered 
by igneous eruptions. 
The bulk of the collection is from the state of New York; but 
there are also many specimens from Canada and Pennsylvania ; all 
these may be considered as one series, since the New York geologists 
have traced their beds into both those countries. There is also a 
most excellent collection from the blue limestone of Ohio, and a few 
from some other beds of the Western States: these have been 
identified with the New York formations, so that the classification 
adopted by the state-geologists of New York forms the basis of all 
the following remarks. 
