38 
NORTH GALLERY. 
[upper 
Wenlock Shale and Limestone of Worcestershire and Staffordshire, and 
the Silurian rocks of Bohemia. The " Dudley Locusts " (Calymene Blu- 
menhachii) and the great "Barr Trilobite " (lUcBmis Barriensis) are 
among the earliest fossils known to science. Fossil Lobsters are 
found to extend from the Coal Measures to the present day; whilst 
true Crabs first appear in the Upper Oolite. Specimens from the 
Lias of Lyme, the Oolite of Solenhofen, and the London Clay of 
Sheppey, are most deserving of attention. 
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 [Bracliiojwda). 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 Terehratula oi 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 
Terehratella, of which all, excepting the last, appear to be verging 
towards extinction, or are scantily represented by existing species. 
The Fossil Bivalves {Conchifera), and Spieal Univalves {Gas- 
teropoda), have been arranged in parallel groups, according to their 
geological age. 
TEKTIARY FOSSIL SHELLS. (Room VL) 
1. Newer Pliocene. The Shells of this Geological period are 
displayed in the Table Cases numbered 11 and 12, and in part of 
Case 13. 
2. Older Pliocene. In Table Case 10, will be found Shells 
of 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. And in part of Table Case 
11 is exhibited a collection of Lithodomous Mollusca, with their 
crypts or cells : they are chiefly from the Crag of Suffolk. 
3. Miocene, or " Middle Tertiary." To this period are referred the 
Shells from Touraine, Bordeaux, and Poland, in Case 6 ; from Malaga, 
Case 4; and from St. Domingo, Case 13. Some of the Shells col- 
lected in the Canary Islands, and in Madeira, by Sir Charles Lyell, 
are referred to the same period : they are also in Table Case 13. 
4. Eocene Tertiary, or London Clay and Paris Basin (Cases 4, 5, 
and 8), Room VI. Not any of these can be certainly identified with 
living Shells; and the species which they most 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. (RoOmS V. & VL) 
5. Chalk, Gault, and Green -sand (Cretaceous System). (Table 
Cases 1 and 2, Room V.) The characteristic Shells of the Chalk are 
