

APPENDIX, 



Descriptions of Fossil Shells of the Collections of the Exploring Ex- 

 pedition under the command of Charles Wilkes, U.S.N., obtained 

 in Australia, from the lower layers of the coal formation in Ilia- 

 warra, and from a deposit probably of nearly the same age at Har- 

 per's Hill, valley of the Hunter; by James D. Dana, Geologist of 

 the Expedition.* 



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, plicse most abrupt on pos- 

 terior side, becoming obsolete laterally, aperture deltoidolunate, a little 

 dilated laterally. — Diameter of species f inch ; thickness through the 

 centre | 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 compressed-lunate, not dilated, the 

 part of the aperture either side of the included body of the shell very 

 narrow; back of the whorls rotund. Thickness at middle half the di- 

 ameter. Resembles a Goniatite, but there are no septa. — lllaivarra. 



3. Platyschisma ? depressum. — Large, very much depressed, subor- 

 wcular, spire very low ; whorls three or four, much flattened, back 

 somewhat truncate, surface without markings excepting striae of growth. 

 -Diameter 4j inches.— Harper's Hill 



4. Pleurotomaria tr if lata. — Shell rather short turreted ; whorls 

 °ur, separated by a distinct suture, back tri-carinate, the middle carina 

 argest, subacute ; aperture orbicular. — Large specimens are eight lines 

 ,0n g> and five broad at base.— Harper's Hill and Illawarra. 



5 - Pleurotomaria nuda.— Shell much depressed, whorls four or five, 

 smooth, rounded, low-carinate, with an obsolete sulcus either side of 

 carina; volutions separated by a distinct suture.— Specimen is f of an 

 ** ^ diameter, and about half an inch in length.— Harper s H ill. 



"• Natica ? Illawarra. 



7 - Patella tenella.— Short conical, apex pointed, slightly recurved, 



^Projecting beyond base ; base oblong ovate, narrowest beneath the 

 J5* length about twice greatest breadth. Length of base § of an 

 ,uch ? height f of an inch. On the specimen, which is a neatly pre- 



Ure* A d ^? ,!ed ****»" of these and other fossils from ^^^£^£^J^ 

 12\ mH *?F** * 'be Government Geological Report by . I h e writer now 

 R >' f (] y & Plication. As interesting associations ^^S^^S^m 

 o!F re ?I' ed ' the ***** would remark, that the species with fe* J»e [JJ*^ 



J aj ned by himself at the localities. He offers here no opinion as to the particu 



^fiiifc. the re* essential aid he » fr* -eived 

 n lf of. Agassiz in the study of many of the speciei. 



