280 Antediluvian Zoology and Botany. 
On the Continent this department was illustrated as early 
as 1775, in Knorr’s magnificent Recueil des Monumens des 
Catastrophes que le Globe de la Terre a essuiées. 
Mr. Sowerby’s Mineral Conchology of Great Britain com- 
prehends the greater portion of our fossil shells. Numerous 
additional species have, however, been described in other 
works; such, for instance, as those by Messrs. Young and 
Bird, Mr. J. Phillips, Mr. Mantell *, and by contributors 
to the Trans. Geol. Soc. From sources so authentic, it is 
possible to form estimates which will now convey some notion 
of the numbers, the prevalence, and the geological distribution 
of our mineralised 'Testacea. The augmentation which such 
a table is capable of receiving is not, in one point of view, 
very material; because it is not probable that the relative 
proportions which the respective classes bear to each other 
will be much affected by such addition. Proceeding at once 
to the result, the numbers and proportions are as follows :— 
Simple Univalves, Gasteropodous Mollusca 
- 62 to 64genera. 
Simple Bivalves, Acephalous Mollisca - -69o0r 71 
Somplicated Bivalves, in ancient formations - - 3— 38 
eee cham ’ Cephalopodous Mollisca - 12 — 12 
bered Univalves af 
In all 146 to 150 genera. 
The geological distribution of species comprised within 
these genera 1s found to be in the following manner: — 
- E 
Simple Uni- aa. Chambered 
valves, inclu- | Simple eS | and Total 
ding the Bivalves. Bival eX | Multilocular ane i 
Tubular Ty av ese Shells. T pecies: 
Species. Species. | Species. Species. : 
In the secondary and 
transition series of 204 629 51 272 1156 
Britain - = 
i form- - 2 ; 
In the tertiary for 295 185 0 | 8 488 
ations - - | 
499 814: Oil, 280 1644 
This number falls greatly short of the entire series. M. Deshayes has 
determined no less than 1200 species in the tertiary deposits alone of the 
Paris basin. 
* Mr. Mantell’s Tabular Arrangement of Sussex Fossils, recently published 
by the Geological Society, furnishes an admirable condensation of local 
zoological information. Mr, J. Phillips’s tables are also arranged with 
great care and ability. 
