M. Blainville on Ichthyolites, 113 
The fossil fish of what is called the metalliferous slate, are well 
known to be abundant, in numbers at least, if not in kinds; and they 
occur in many different places. The most noted of these are the 
Palatinate, the Voigt, and Thuringia; and they have often been de- 
scribed by different authors, such as Kruger, Friesleben, and others. 
It is somewhat remarkable with respect to these specimens, that they 
are almost always much distorted and injured ; not even being com= 
pressed and preserved laterally, as is the most usual case in the fossil 
fishes, It is equally so, and important at the same time in investi- 
gating the species, that the impressions are those of the skin and sub- 
stance of the animal, not of the skeletons. 
With respect to the nature of this deposit, we have no objection to 
be convinced that it is a marine one, if it appears that any one of the 
fish is marine, or that any one sea-shell is contained in it. It may 
very probably be so, although no such evidence is produced. But if 
we are willing to believe quietly and without any evidence at all, we 
do not choose to be obliged to believe by that which is not evidence ; 
and this, not on account of any concern we feel about the bitumino- 
metalliferous schist of Mansfeld, but because of the very testimony 
itself. We have a mortal aversion to corrupt evidence in all its 
modes, and do not choose to pass any attempts to introduce any more. 
of it into geology, where there is already an abundance. 
These strata are determined to be marine because they lie beneath 
calcareous rocks containing ‘‘ ancient” (or modern) marine shells, 
such as belemnites, entrochites, and ammonites, of the same kind as 
those that belong to the limestones of the Apennines and Alps, toge= 
ther with gypsum accompanied by sea-salt, gypsum without sea-salt, 
sandstone, and so forth. Now these strata are the exact counterparts 
of the red marl and lime of England; particularly where they are 
somewhat intermixed. We have no objection, either to their marine 
origin, or to their antiquity, if that will give Monsieur Blainville any 
satisfaction ; but neither of these will prove that the strata below them 
are of marine origin also. Our own coal strata are situated in this 
very position; and no one now, it is hoped, since the theories of 
Dr. Hutton and of Kirwan on this subject are forgotten, will imagine 
that a series which contains terrestrial vegetables in abundance, and 
which never was known fairly to include a seashell, is of marine 
origin. ‘Thus much for what is possible respecting this deposit of 
ichthyolites. 
Monsieur Blainville has made twelve species and three new genera 
out of this collection. The new are palzoniscum, paleothrissum 
and stromatcus : the old ones clupea and esox. In general we may 
remark on these determinations, that they are more free from objec 
tions than some of the preceding ; as the author had access, in many 
instances at least, to more perfect specimens. How far, however, his 
arrangements are justified, we cannot pretend to decide. We may 
Vou. XVII. 
