Prof. Necker on the History and Progress of Geology . £95 
of the highest interest, that the Geographie Mineralogiqut des 
Environs de Paris , deserves the high reputation which it enjoys. 
Nor yet is it for the complete description of these formations, so 
remarkable for the alternation of mobile with solid strata, and 
by those of masses full of shells and animals, which inhabit the 
land or fresh water, with petrified strata of the remains of ma- 
rine animals *; but it is as a perfect model of geological investiga- 
tion that this work should be particularly cited ; and, moreover, 
as having enriched geology with a new class of distinctive cha- 
racters, taken from the constant presence of certain genera, or 
of certain species of animals in the same strata. All the ques- 
tions relative to the distribution of fossil organic bodies, in 
the strata of greater or less antiquity, to the identity or diffe- 
rence of these animals with the analogous species which exist at 
the present day, had been strongly recommended to the exami- 
nation of geologists in the Agenda of Saussure ; but, until un- 
dertaken by Messrs Cuvier and Brongniart, these problems, 
equally difficult as important, had found no one capable of re- 
solving them. 
M. Brongniart is at present pursuing the examination of the 
zoological characters, in the more recent strata of secondary for- 
mations, and continues to add with Ferussac, Sowerby, Schlot- 
theim and Wahlenberg, new species of fossil shells to the cata- 
logue commenced by Bruguiere, Montfort and Parkinson, and 
much enriched, and methodically classed by Lamarck. 
The Crustacea of M. Desmarest, the fossil vegetables of M. 
Adolphe Brongniart, and the immortal work of M. Cuvier, up- 
on the osseous remains of the vertebral animals, show the as- 
tonishing impulse given by men, animated with the true and phi- 
losophical spirit of investigation, to this interesting part of the 
history of the globe, where all the branches of Natural History 
seem to unite and amicably join hand in hand, to penetrate to- 
gether into the obscurity of those vast catacombs, overwhelmed 
with the debris of the antediluvian world. 
The labours of Messrs Cuvier and Brongniart, have given 
anew a favourable direction to Zoology. Their discoveries have 
* De Luc and De Saussure had already shewn fresh water fishes and shells in 
strata connected with marine deposits. 
