PLATE XXVI. 
SILURIAN SPECIES. 
Fic. 
120: Porambonites? intercedens, var. filosa? Caradoc; Dunabrattin, Waterford. 
Mus. Geol. Survey, Ireland. 
oh Ka ,, Wrae Quarry, Peebleshire. Woodwardian Museum, 
Cambridge. 
4—9. Orthis Lewisii, Dav. 6—8. Wenlock Limestone; near Dudley. 8a. Interior 
of ventral, and 84, of dorsal valve, enlarged. 9. 
Internal cast of dorsal valve, from Wenlock Shale ; 
Pentland Hills, Scotland. 
10—15. » biloba, Linné, sp. A series of variations in shape and age. Wenlock 
Limestone; Walsall, Dudley, Buildwas, Pentland 
Hills, &c. 12. Caradoc; Cefn-Rhyddan. Mus. 
Geol. Survey. 
16—23. »  Bouchardii, Dav. 16—22. Several variations in shape and age, from 
. the Wenlock Limestone of Benthall Edge. 22. In- 
terior of dorsal, 22a, imterior of ventral valve, 
enlarged. 23. A specimen from Penwhapple Glen, 
Ayrshire, in Mus. Geol. Survey, supposed to be from 
the Llandovery beds. 
