A Manual of Elementary Geology / or, The Ancient Changes of the Earth and its Inhabitants as Illustrated by Geological Monuments

by Sir Charles Lyell

Fig. 403.

Calceola sandalina, Lam. Eifel; also South Devon.

• a. both valves united.
• b. inner side of opercular valve.

Fig. 404.

Strygocephalus Burtini. (Terebratula porrecta, Sow.) Eifel; also South Devon.

• a. valves united.
• b. side view of same.
• c. interior of larger valve, showing thick partition, and thinner one continued from it.