464 Royal Institute of France. 
eurrent, and we pass from this rock by intermediate ones, com- 
parable to trapps properly so called, to the common basalt, con- 
taining frequently peridot, and some parts of which De Saussure 
saw divided into prisms. There is also some vacque or wack 
which serves as the basis of the amygdaloid, and which when 
its cellules are empty completely resembles a porous: lava; but 
in which they are most frequently filled with limestone, as in 
the mandelstein of the Germans. Lastly, we find a basaltic tufa 
filled with smal] calcareous buttons, and containing pyroxeneés, 
peridots, micas, and these other mineral species so common in 
the Javas. M. Mesnard saw at Beaulieu a hollow which ap- 
peared to him Jike the remains of a crater. He concludes there- 
fore, after some general reasoning against the objections of the 
Neptunists, that this mountain was the production of a sub- 
marine eruption, and that the sea in which it was made con- 
tinued for a long time afterwards to deposit limestone. De 
Saussure had already appeared to be favourable to this opinion, 
M. Faujas St. Fond regarded it as incontestable, and M. Mes- 
nard thought he saw in ita method of conciliating all opinions 
on the pretended secondary trapps, which have been so long a 
subject of dispute, 
Among those numerous fragments of unknown organization 
which fill the strata of the earth, there are found impressions of 
an animal of a singular form composed of a sort of corslet, and 
an abdomen formed of several segments, each of which is di- 
vided into three lobes. Naturalists have given them the names 
of entomolites and trilobites; but they have not sufficiently di- 
stinguished them from each other, and have not determined to 
what order of stratification each species belonged. 
M. Brongniart, the manager of the manufactory of Sevres, has 
presented a work on this subject, in which, after an exact com- 
parison of the specimens which he procured, as well as of the 
deseriptions and figures left by preceding authors, he shows 
that there are at least seven species of these trilobites, that their 
ptincipal forms are sufficiently distinct to divide them into four 
genera, which ought to be all ranged in the class of crustacez, 
and in the order of those whose gills or lungs are exposed to view. 
The most of those trilobites belong to the deepest, 7. e. the most 
ancient of the stratifications of the soils which contain animal 
remains; they must therefore have been among the first ani- 
mated beings; and in fact, as we approach the surface, we find 
crustacee hore similar to those now contained in the sea; but 
the trilobites have disappeared entirely. 
M. Cordier has published a memoir on the coal-mines of 
Franee, and on the progress which has been made in their 
working for the last twenty-five years. He proves that in this 
interval 
