34 
NORTH GALLERY. 
[UPPER 
The Fossil Shells (Mollusca) are divided into four groups? 
1. Lamp-shells (Brachiopoda). 2. Ordinary Bivalves (Conchifera). 
3. Spiral Univalves (Gasteropoda). 4. Chambered Univalves {Cepha- 
lopoda). 
Lamp-shells (Brachiopoda). Cases 2 and 3, Room VI. Those from 
the Tertiary strata belong to existing genera, and some to existing 
species ; but others, like the great Terebratula of the Suffolk crag, are 
unknown in a recent state. The Chalk species are no longer living, and 
belong chiefly to the genera Terebratula, Thecidium, Rhynchonella, and 
Terebratella, of which all, excepting the last, appear to be verging 
towards extinction, or are scantily represented by existing species. 
The Fossil Bivalves (Conchifera), and Spiral Univalves (Gas- 
teropoda), have been arranged in parallel groups, according to their 
geological age. 
TERTIARY FOSSIL SHELLS. I f<T» 
1. Newer Pliocene. Table Case (11), Room VI., contains a series- 
of Shells from raised sea-beds and beaches in Scotland, Sweden, and 
North America : these shells are of a more Arctic character than those 
now living in the adjacent seas. Table Case (11) contains a similar 
series from Sicily. 
2. Older Pliocene. Table Case (10), Room VI., contains Shells, 
from the " Crag " of the eastern counties, of which more than half 
are still existing, either in British Seas, in the Mediterranean, or on the- 
coasts of Norway and North America. 
3. Miocene, or " Middle Tertiary." To this period are referred the 
Shells from Touraine and Bordeaux (Case 6), from Malaga (Case 4), 
Shells from St. Domingo (Case 11), Room VI.; and part of those 
collected by Sir C. Lyell in the Canary Islands and Madeira 
(Case 13). 
4. Eocene Tertiary, or London Clay and Paris Basin (Cases 4, 6>, 
and 8), Room VI. Not any of these can be certainly identified with 
living Shells; and the species which they may resemble are now 
found at the Cape of Good Hope, the western coast of South America,, 
and other localities remote from those where the fossils have been 
found. 
SHELLS OF THE SECONDARY STRATA. 
5. Chalk, Gault, and Green-sand (Cretaceous System). (Table 
Cases 1 and 2, Room V.) The characteristic Shells of the Chalk are- 
Inocerami, related to the recent Pearl-oyster ; Spondyli; Scallops (Pec- 
ten), of peculiar form ; " Cockscomb " oysters, and species of Lima 
and Pleurotomaria. One peculiarity of the Chalk Fossils is, the con- 
stant absence of the interior pearly layers of the shells, which have 
been removed subsequent to their imbedding. In the Green-sand 
strata, Trigonia abound, and peculiar bivalves, of an extinct family (Hip- 
puritida), related to the recent Chama. Case 1, Room VI.) 
G. Jurassic, or Oolitic Shells. (Cases 2 and 3, Room V.) The 
