INTERESTING ACCOUNT OF THE DISCOVERY OF FOSSIL FISH. 279 
longer suited to external nature, — the whole 
order therefore perished. 
Did then these vast alterations in the plan 
of nature take place suddenly"? Was this 
immense destruction, not only of animal life 
but of a whole system of organization brought 
about at one time ?— in a short time ; or did 
it take place by more gradual changes? by a 
series of changes so slow as to be imperceptible, 
going on through a countless series of ages? 
M. Agassiz has introduced some remarks 
bearing on the solution of these questions. He 
observes that, in some cases, local and tran- 
sient causes may be capable of producing such 
effects over a certain extent of district : such, 
for example, as volcanic eruptions. A sub- 
marine eruption might destroy all the fish in 
the particular region where it took place ; but 
this would hardly account for the disappear- 
ance of species diXiA genera, however extensive 
or often repeated. M. Agassiz possesses spe- 
cimens in which a great number of fossil 
fishes are crowded into a small space ; and the 
appearance of the whole is such, as to impress 
the spectator with the belief that they were 
destroyed and imbedded, as it were instan- 
taneously, by some sudden catastrophe: such 
as a sudden eruption of volcanic matter, ora 
sudden influx of fresh water, or even the heat- 
ing of the sea by a submarine volcano. 
Such causes as these, however, could be 
only local ; and it is evident we must refer to 
changes, upon a much larger scale, in the 
condition of the earth’s surface, as alone capa- 
ble of producing the greater effects we have 
above described. M. Agassiz appears to lean 
to the theory of those geologists, who contend 
that the great changes which have affected 
the crust of our globe were brought about by 
vast and sudden catastrophes and that, cor- 
responding with the occurrence of these con- 
vulsive movements, the great changes in the 
characteristics of animal and vegetable life 
were as suddenly introduced. Those of our 
readers who have perused the masterly but 
extremely popular work of Mr. Lyell (and 
we hope there will be few who have not), will 
know how to estimate the claims of this 
theory. 
M. Agassiz commenced his researches on 
the Continent ; but has, more recently, 
extended them to an examination of tlie 
specimens fourid in English collections. 
Here, indeed, we have been long accu- 
mulating these geological treasures, in 
which our island is peculiarly rich, but with- 
out' fully understanding the value of them, 
until M. Agassiz has pointed it out to us ; and 
invested many of these accumulations of neg- 
lected remains, with a new value and interest. 
He has found, in the English cabinets, 300 
species new to his researches. Here, then, 
was an interesting, perhaps critical, moment 
for his speculations ; his views were thus put 
to a severe test. All these specimens, however, 
were found to furnish a complete verification 
of his former inferences, and entirely to corro- 
borate the laws ofdevelopment which he had 
previously determined, in regard to the suc- 
cession of these orders of animals, during the 
different changes which our globe has under- 
gone. 
The oldest formation in which fossil fishes 
are found, is the Silurian system of rocks; in 
which there are five or six species, exhibiting 
the first appearance, in the primaeval world, 
of this long-continued series of vertebrated 
animals ; the species of which become more 
and more diversified and numerous, as well 
in their outward forms as in their organiza- 
tion, as we advance to the later formations. 
Yet, as we have- indeed already noticed, 
those which do occur even in these most 
ancient rocks, the first of living beings which 
tenanted the globe, were animals of the most 
perfect and exquisite structure and organiza- 
tion. 
A highly interesting account has lately been 
given to the Geological Society, by Mr. Mur- 
chison, of the discovery of fossil fish , in the 
new red sandstone of Tyrone, in Ireland, 
being the first discovery of such remains in 
the particular stratum, though they were 
known to exist in others of the group to which 
it belongs. The part of the formation in 
question surrounds, and includes, a small 
coal-field, but reposes, for the greater part, 
on mountain limestone. The sandstone con- 
sists of many distinct beds, which have evident- 
ly been deposited at different, and widely 
separated, periods of time; since some of the 
lower exhii'it, on the upper surface, the marks 
of the rippling action of water, and must, 
therefore, have long presented an exposed 
surface to a calm sea. It is in the lowest beds, 
twenty-five or thirty feet below the surface, 
that tire fishes are found. 
Another curious and interesting fact, con- 
nected with these researches, has been the 
light thrown by them upon some very singular 
specimens, which had been, for years, in the 
possession of Dr. Buckland, but of which nei- 
ther he, nor any of the numerous geologists 
and naturalists who examined them, could 
make out anything. They are now ascertain- 
ed, by comoaiison, to be the jaw-bones of a 
rare fossil fish, of which four different species 
are now recognised, in the oolitic formation, 
by the acute investigations of Dr. Buckland. 
We have alluded to some remains of fossil 
fishes, which bear a resemblance to those of 
the Saurian reptiles, (the tribe including the 
lizards and crocodiles). We must not omit 
one very remarkable instance, which throws 
considerable light on this sort of relation. 
In the limestone of Burdie-house, in Scot- 
land (belonging to a deep-seated bed of the 
coal formation, beneath all the beds of coal), 
numerous specimens of fossil fish were dis- 
covered by Dr. Hibbert, a few years ago. 
Amongst other remains, he has since found, 
in this locality, many specimens of teeth, 
scales, and large bones, apparently of a Sau- 
rian character. This being mentioned to M, 
Agassiz, he at once traced an analogy which 
has enabled him to explain, with the highest 
probability, the nature of the animal to which 
they belonged. In the tropical parts of 
