266 
On the Organic Remains 
[Sept, 
found in both being identical, and some of them peculiar to that member of 
the newer strata, no doubt is left of their correspondence in order and position, at 
least in the mind of the experienced geologist. 
The application of this test to rocks in the same neighbourhood must at once 
be admitted as legitimate ; that it may be extended even to rocks of the same 
country most will concede ; but in pushing the principle still farther, it will become 
a subject of consideration what is the postulatum on which the deductions from it 
rest. In ' applying it to rocks found on opposite sides of the globe and in 
climates the most different, do we not assume that similar animals must have lived 
in widely separated localities, in climates sometimes directly opposite ? Again, what 
do we mean by similar animals ? Does the term include the same species, or merely 
different species of the same genus ? Here are questions which can only be answered 
by an extensive induction. If answered affirmatively, they would afford a certain 
clue to the investigation of many curious facts in distant countries ; but they unfor- 
tunately require for their answer those very facts they are intended to illustrate. 
Geologists have perhaps too hastily adopted the least troublesome view of the 
question, and have, I think I may say, assumed what should have been the object 
of their inquiry. It has in this way, for instance, been attempted to connect the 
strata of the Himmalaya in which organic remains are found, with the secondary' 
and tertiary strata of England. Geology is not however yet ripe, for the admission 
without question of the opinion on which this conclusion rests ; and many more 
facts must be collected before it can be viewed as even probable. In a question 
of this nature, in which very distant localities are concerned, we should find mineral 
composition, notwithstanding its latitude, a safer guide ; for as Humboldt observes, 
the rocks are the same in every climate, but not so the organic productions whether 
animal or vegetable* What is meant is, that though rocks oscillate much, their 
oscillations are performed round a mean type, which is the same in every country 
however different the locality. Even the oscillations preserve a certain resem- 
blance ; and however great the varieties may be of a rock found for instance in one 
country, similar types will be found wherever else that rock is extensively develop- 
ed. But the case with organic productions is very different. Amongst them the 
instances are few of an individual adapted to live in different climates; and even in 
the same climate, how often do we observe individuals confined to a limited range, 
where the arrangement of nature has been undisturbed by man ? Perhaps however 
the opinion, which would advocate the comparison of mineral composition as a 
means of determining the identity of the supposed member of any formation, is 
applicable with less modification to the primary and secondary than to the tertiary 
class of rocks ; although I conceive we are far from being able to pronounce posi- 
tively, without a much more extensive collection of observations than we can jet 
command. 
The tertiary strata in Europe have been fully studied, owing to the abundance 
and variety of the organic remains found in them ; but we have as yet few notices 
of these strata in other parts of the globe. These tertiary strata have hitherto been 
found in countries of moderate elevation : it is not unlikely then, should the 
conjecture which traces them in the Himmalaya mountains prove to be well 
founded, that the examination of them at such enormous elevations may be attend* 
ed with the discovery of various particulars of interest, and it is much to be desir- 
ed that the subject could be prosecuted with that energy which its importance 
warrants. But for this very reason I would argue against our receiving too easily 
the opinion, which from the examination of a few shells would at once jump to the 
