M. Blainville on Ichthyolites. 119 
remains are preserved. It would be easy to state a rational theory 
of this formation, and its relations to parallel phenomena in many 
parts of the world: but they are in a good measure superseded by 
the present more rational views of the history of the supramarine or 
ganiferous strata. 
We said before, that it was incumbent on an author, professing to 
give a general treatise on ichthyolites, or of any other branch of 
this .science, to make himself acquainted with the facts at least 
which are accessible, or to acquire such knowledge as would enable 
him to profit by the observations of others. The defect of our author 
in these respects is peculiarly sensible in what follows, where he has 
copied careless observations in a careless manner, and rendered the 
confusion more offensive and troublesome by the systematical and 
decided form in which he has placed it. Mount Lebanon, Cerigo, 
Antibes, and many other localities are discussed in this slovenly man~= 
ner, from Faujas de St. Fond, and others; and where we ought to 
have certainty we have only useless guessing. 
We consider that an author who thus professes to write a syste- 
matical work, is bound to make it really systematical, as far as that is 
possible. Icis a different thing to write single essays, or to describe 
those separate localities and partial facts from which geology ulti- 
mately derives assistance towards its general views. Hence our 
author is equally deserving of censure, that when he quotes Sicily, 
Malta, Iceland, and other well known countries, where fossil fishes 
have been found, he is scarcely ever at the trouble of ascertaining 
what has already been written about them, or of trying to extract 
something like truth from a balance of testimonies. As a specimen of 
this unpardonable carelessness, he quotes Antibes as a locality, and 
then doubts whether itis not Antigua. Nor could any thing but the 
same ambition to make a book and a system, which has led him to 
give genera without descriptions and species, under such imaginary and 
nominal genera, have tempted him to muster in his arrangement the 
fossil fishes of China, of which he knows nothing. On those of England 
he is equally unsuccessful; whereas he might have found something 
to his purpose, had he taken the trouble to seek for it. 
We have already shown our suspicions that many of Mons. Blain- 
ville’s marine formations, and marine ichthyolites, are really fresh 
water examples ; but we have a detail in the latter part of his essay of 
those which are indisputably such, and which he chooses to call Po- 
tamiens, “‘ apparemment,” because Tora is a river, and that these 
strata have been produced in lakes. 
We may pass over the Italian examples, as unsatisfactory: those 
of France are better known, and are here better described. ‘The 
deposit of Aix is well known to consist of five marked beds, reaching 
toa depth of near sixty feet, consisting of marl, limestone, bitumi- 
nous marl slate, and gypsum. ‘The fishes which it contains are one 
species in the genus perca, acyprinus, and the mugil cephalus or 
