24 
MIDDLE CAMBRIAN. 

Case and 
Column of 
Drawers. 
Reference to McCoy’s 
Synopsis: and Figures of Genera. 
Names and References; Observations, &c. 

Gi 
Gi 
Gi 
case 
case 
Gi 
Brachiopod Shells. 


Lamellibranchs. 







Orthis Carausii, Salter (Davidson, Earliest 
Brach. Geol. Magazine, Vol. v. pl. 16, fig. 23). 
Short, squarish, with 16 simple ribs. 
Orthis , sp. (O. calligramma of some 
works, but a distinct species). 


Orthis Menapie, Hicks (Davidson, 1. c. pl. 16, 
figs. 2428). The fine ribs distinguish this 
from the species above described. 
Obolella? plumbea, Salter (Lingula, Mem. Geol. 
Surv. Vol. mr. pl. 11 8, fig. 10: Davidson, 
Sil. Brach. pl. 4, figs. 20—27). Obolella is 
a genus only ranging from the lower part 
of the Middle Cambrian to the base of the 
Upper Cambrian. 
Obolella plicata, Hicks (Davidson, 1. c. pl. 4, f. 6). 
Obolella, sp. small and round. The species of 
all the horny Brachiopods are very difficult 
to separate one from the other. 
Palearca socialis, Salter (Mem. Geol. Surv. 
pl. 11 , fig. 13, p. 344). The genus is bet- 
ter represented in the Bala rocks (see Mid- 
dle Bala). 
Ctenodonta elongata, Hicks (undescribed). The 
genus like Nucula, but the ligament ex- 
ternal. 
Ctenodonta rotunda, Hicks (undescribed). 
Theca Harknessi, Hicks (undescribed). The 
surface finely reticulated by striae in two 
directions. 
Conularia Corium, Salter (Mem. Geol. Surv. 
Vol. mi. p. 355, pl. 11 a, fig. 11). A very 
large and thin species, with perfectly smooth 
sides, and a squarish section. Like C. pyra- 
midata, Desl. from Normandy, and possibly 
the same. 
Orthoceras, small sp. The genus is rare in this 
formation. 
Numbers and Localities. 


a. 485, Ramsey 1, N. End. 
Base of the whole group. 
(Dr. Hicks.) 
Carn Goran, Cornwall, in 
hard quartzite. 
a. 291, Lower Arenig rocks, 
St. David's. (Dr. Hicks, 
1869.) 
a. 57, White Grit Mine, 
Shelve. (Mr. R. Light- 
body.) 
a. 292, Tremenheere, St. 
David’s. (Dr. Hicks.) 
b.359, Ty Obry, near Garth, 
Portmadoc. (Mr. Hom- 
fray.) 
b. 359, Ty Obry, Portma- 
doc. (Mr. Homfray.) 
a. 469, Ramsey I, North 
End. (Dr. Hicks.) 
a. 469, Ramsey I, N. 
End. (Same slab as last.) 
a. 299, Upper Arenig rocks, 
Whitesand Bay. (Dr. 
Hicks.) 
b. 3638, Ty Obry, Garth. 
(Mr. Homfray.) 
b. 349, Ty Obry, do. (Mr. 
Homfray.) 
