1848.] RAMSAY AND AVELINE ON THE STRUCTURE OF WALES. 299 
gramma and QO. expansa also occur, and Turbinolopsis bina and 
Favosites multipora. The presence of abundance of Pentamert in 
the upper parts here reminds us of the Lsquire Hall Quarry. 4 
Summary. 
The fossil evidences here cited indicate— 
1. That the sandstones skirting the Longmynds are the upper 
beds of the Caradoc. 
2. That they were deposited under peculiar local conditions. 
3. That they were deposited around the margin of land. 
4. That in all probability they were deep-sea deposits around high 
and steep land. 
5. That the land was of Llandeilo flags_or older rocks. 
6. That they are in sequence with the limestone bands at the base 
of the Wenlocks. 
7. That part of the Meifod fossiliferous beds are in a lower parallel, 
and probably Middle Caradoc. 
Note by J. W. Satter, Esq., on the Fossils of the lowest Wenlock 
Shales east of LLANDEGLE, BUILTH. 
In the following list there is a mixture of Upper and Lower 
Silurian species, 7. e. of Caradoc and Wenlock shells; it consists of 
Trilobites and Brachiopod shells, and a single coral. 
The Brachiopods are partly the same as those of the Llandeilo flags, 
but only because such are widely distributed species, partly the same 
as those of the Caradoc districts, such as Church Stretton, May Hill, 
&c., and partly Wenlock species. 
The absence of ordinary bivalve and univalve shells, and of Cepha- 
lopoda and Bellerophons is very curious, and but one coral is present 
—the universal Turbinolopsis. 
Although apparently a mixture of Upper and Lower Silurian, the 
group is not at all like the Woolhope limestone, being deficient in 
Terebratulee, large flat Orthides, corals, and characteristic Trilobites. 
Nearly all the species are found in Upper Caradoc. 
_ The most abundant Trilobite, Cybele punctata, ranges to the tile- 
stones near Builth. 
Cybele punctata (abundant); Cheirurus speciosus’?; Illenus, 
fragments ; Calymene Blumenbachi ; Tentaculites annulatus ; Lin- 
gula, sp.; Orthis calligramma, O. testudinaria and O. elegantula, 
small; Strophomena applanata; S. expansa, a Lower Silurian 
species ; Leptena sericea, variety with faint strie* ; L. transversa- 
lis*, common; L. depressa, small; <Atrypa reticularis*, most 
plentiful ; Atrypa, a smooth convex species; A. undata*, plentiful, 
a Llandeilo flag shell; Terebratula didyma; Spirifer radiatus, 
Sowerby?; Terebratula marginalis*, common ; Turbinolopsis bina*. 
{Those marked with an asterisk are characteristic species of the 
uppermost beds of the Lower Silurian in the Vale of Meifod—con.- 
sidered as passage beds by Prof. Sedgwick. | 
