62 
THE GEOLOGIST. 
MOLLUSCA. 
Oi-thoceras sulcatum, Flem. 
Goldfussianum, Kon. 
Nalicopsis I'tlicistria, Phil. 
Loxonema rugifera, Phil. 
jEuomphalus carhonarius, Sow. 
Pleurotomaria decipiens, McCoy. 
atomaria, Phil. 
PlatyacMsnui helicoidcs, Sow. 
Bellerophon Urii, Flem. 
Orthis resupinata, Mart. 
. Micheliiii, Kon. 
Strophomena crenistria, Phil. 
Productus Martini, Sow. 
. punctaius, Maxt. 
scahriculus, Mart. 
■ spinuloms. Sow. 
fimhrialus, Sow. 
latissimus, Sow. 
Flemingii, Sow. 
semireticulatus, Mart. 
Chmetes sordida. Sow. 
Dalmaniana, Kon. 
gibberula, McCoy. 
Spirifer trigonalis, Mart. 
glaber, Mart. 
Uneatus, Mart. 
octoplicatHS, Sow. 
Edmondia sulcata, Phil. 
SanguinoKtes iridinoidcs, McCoy. 
transversa. Port. 
variabilis, McCoy. 
Aviculo-pectcndocens, McCoy. 
BRYOZOA. 
Fenestella plebeia, McCoy. 
crassa, McCoy. 
undulata, Phil. 
Glauconome pluma, Phil. 
Sidcoretepora parallela, Phil. 
CORALS. 
A u lopliyll um fungites, Flem. 
Lithodendron irregulare, Phil. 
Stenopora tumida, Phil. 
Favosites parasitica, PhO. 
serialis, Port. 
The calcareous shale is remarkably full of fossils ; indeed it is 
almost entirely formed of Productus Flemingii and Spirifer trigonalis. 
Being exposed to the weathering influence of the tide, which washes 
away the softer matrix, the fossils stand out in bold relief, and fine 
specimens of the Productus can be obtained, showing beautifully the 
curious internal structure of the shell. 
The limestone which forms the bold headland of Ebbs Nook is, 
however, the most interesting of the group, from its peculiar orga- 
nisms, its mineral composition, and picturesque appearance. It is 30 
feet in thickness ; and, being very hard, resists more effectively than 
the other rocks the destructive action of the sea. Resting, however, 
on a soft shale which is easily broken up and washed away by the 
tides, this superincumbent limestone is deprived of support, and from 
time to time large masses tumble down from the cliff. It now forms 
a narrow point running out into the sea for about one quarter of 
a mile ; but the tides and high seas are still working away the lower 
and softer beds which connect this pi-omontory with the land, and in 
the course of a few centuries it will become an island on the flow of 
every tide. This limestone is of a buff colour and generally of a 
crystalline structure. It is a magnesian limestone, being composed of 
carbonate of magnesia and carbonate of lime. Besides containing 
