221 
Horizon and Localities. — Mr. J. D. Dana found it at Black Head, 
in the Illawarra District, and Mr. W. B. Clarke at Wollongong in a red 
sandstone. 
MiEONiA GRACILIS, J. J). I)ana} 
PL XIX, Pig. 1. 
Cleohis gracilis, J. D. Dana, 1847, Am. Journ. Sci., IV (2), p. 154. 
IHceonia, ,, Idem, 1849, Geol. Wilkes’ U.S. Explor. Exped., p. 698, pi. 7, fig. 1. 
This shell is of moderate size, elongated, oval, and a little angular 
posteriorly. Its beaks are thick and anterior, its ventral margin regularly 
curved, its anterior margin rounded, and its posterior margin slightly arched 
and obliquely truncated. The external surface is not keeled, and is covered 
with indistinct, irregular, concentric wrinkles. The internal structure of the 
valves is unknown to me. 
Dimensions. — The length is eight, breadth is five and a half, and 
thickness about four centimetres. 
Delations and Differences. — This species is distinguished from M. 
grandis by the angular form of its posterior margin, and the greater 
irregularity of its superficial concentric folds. 
Horizon and Localities. — Dana found this at Wollongong, and Clarke 
in the Muree Quarries. 
PLEUBOPIIOEUS, TV. King. 
Pleuropiiorus morrisii, L. G. de Koninck. 
PI. XX, Pig. 5. 
Orthonota ? costata, .1. Morris, 1845, lu Strzelecki’s Pliys. Descr. N. S. Wales and Y. D. 
Land, j). 273, pi. 11, fig. I, 2 (non 'Fteuroptwrus costatus, Brown). „ 
This is a very inequilateral, elongated shell, with the hinge line and 
ventral margin sub-parallel, the anterior margin rounded, and the posterior 
margin slightly and obliquely truncated. Its beaks are small, straight, and 
very anterior. The external ligament is much elongated, its lunule narrow 
1 [R. Etheridge, Junr., Journ. R. Soc. N. S. Wales, 1880 [1881], XIV, n. 251. 
Fossils (Pal. Indica), 1891, IV, Pt. 2, p. 143, t. 8, f. 5.— W.S.D.] 
Waageii, Salt Range 
