APPENDIX. 
* 
Descriptions of Fossil Shells of the Co 
pedition under the command of Cuartes WixxeEs, U.S.N., obtained 
in Australia, from the lower layers of the coal formation in Illa- 
llections of the Exploring Ex- 
bak 
1. Bellerophon undulatus.—Sparingly compressed, back of whorls 
rounded, surface smooth, having a series of distant plications crossing 
the back parallel with the lines of growth, (or nearly V shape with the 
angle rounded,) giving it an undulate outline, plicee most abrupt on pos- 
terior side, becoming obsolete laterally, aperture deltoido-lunate, a little 
dilated laterally.—Diameter of species 3 inch; thickness through the 
centre 3 of an inch; about four plications in a distance of half an inch. 
—Harper’s Hill 
2. Bellerophon strictus.—Discoid, much compressed, smooth and 
without markings, aperture narrow compr -lunate, not dilated, the 
1 
bicular, spire very low; whorls three or four, much flattened, back 
somewhat truncate, surface without markings excepting strize of growth. 
—Diameter 44 inches.—Harper’s Hill. 
_ 4, Pleurotomaria tri-filata.—Shell rather short turreted ;_ whorls 
four, separated by a distinct suture, back tri-carinate, the middle carina 
largest, subacute ; aperture orbicular.—Large specimens are eight lines 
leurotomaria nuda.—Shell much depressed, whorls four or five, 
not projecting beyond base ; base oblong 
beak, length about twice greates gth 
inch; height 2 of an inch. On the specimen, which is a neatly pre- 
ile sin ‘and other fossils from Australia, ill t b 
ae ponatoiag asa iat Geological Report by “the wriler, “now 
ures, will appear in the Gover 
lar age of the deposits. ges: 
Id acknowledge the very essential aid 
from Prof. Agassiz in the study of many of the species. 
he has kindly received 
