554 Reviews— Haswell— On the Pentland Hills. 
fur while the essay is a good one for a first in geology, it scarcely 
deserves to form a separate publication. We say not this in a fault- 
finding spirit, for the perusal of the paper has given us pleasure, 
and we are certain that experience and continued observation will 
give the author a position in science.. But the determination of 
species is no easy work, and it is specially difficult with fossils ; and 
those which form the subject of this paper are more than ordinarily 
so. Before one ventures to add new names, the whole matter 
should be thoroughly wrought up, else endless synonymy—the 
curse of systematic Natural History—creates endless confusion. 
We hope that this paper will incite (and it will certainly assist) 
local students to an examination of these beds, and that before long 
we may see—not a new edition—but a new work, in which Mr. 
Haswell will go more thoroughly and systematically into these very 
interesting fossil-remains. He has already obtained several new 
species; and from the materials collected, he considers the strata to 
be the representatives of the Ludlow and Wenlock deposits. 
V.—StTRATA IDENTIFIED BY ORGANIC REMAINS. 
THE QUARTERLY JOURNAL OF SciENCE (No. VIII.) for October 
contains, in addition to the usual Chronicles of Geology and Palzon- 
tology, an interesting article by Mr. Henry M. Jenkins, Assistant 
Secretary to the Geological Society of London, on ‘Strata Iden- 
tified by Organic Remains.’ 
<« Strata Identified by Organized Fossils,” was the title of a well- 
known work by William Smith (in 1817), in which he illustrated 
his discovery that the numerous formations constituting the crust 
of the earth could be distinguished and identified by means of their 
embedded fossils.’ 
This grand generalization of the ‘Father of English Geology’ 
inaugurated the dawn of a new era in our science, and has neces- 
sitated the establishment of the sister science, Paleontology. 
Mr. Jenkins relates the progress, step by step, of geological inves- 
tigation, and tells how Edward Forbes, in 1846 (29 years after the 
publication of William Smith’s celebrated work), announced that 
identity of fossils in strata geographically far apart, must lead to 
the inference that the beds were of different, not, as hitherto main- 
tained, of the same age. But it appears this new doctrine did not 
produce any permanent effect, and another period (16 years) is 
passed, when Professor Huxley, in his Anniversary Address to the 
Geological Society, again brings this heterodox notion before its 
members, since which time, several of our younger Palzontolo- 
gists, including the author of the paper, have given the idea its due 
weight in endeavouring to correlate distant deposits. 
‘The views of Geologists on this question must depend more or 
less on their belief in the origin of species by descent with modi- 
fication, and from single specific centres.’ 
Mr. Jenkins proceeds with his case, stating, we think, fairly, the 
arguments pro and con, the doctrine of the migration and mu- 
