248 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
there are casts and imperfect examples of the same species which 
show that it is not uncommon. ‘They are all single valves. 
Loe. Wollumbilla. It is named after W. P. Gordon, Esq., of 
Wollumbilla, through whose assistance many of these fossils have 
been collected. 
21, Lima muntistRiata, sp.n. Pl. XII. fig. 5. 
Shell very convex, oblique; auricles very small; hinge-border 
very narrow; surface with about forty depressed rounded coste, 
with narrow interstitial spaces. 
The surface of this shell is somewhat abraded, and its frontal 
margin is incomplete. It is very convex or inflated towards the 
umbones. Only one specimen is known, which is from Wollumbilla. 
22. Pucten (?) meuittngatus, sp.n. Pl. XI. fig. 11. 
Shell ovately orbicular, moderately convex ; surface covered with 
numerous raised divergent longitudinal striz, crossed by about the 
same number of equally raised concentric coste, which narrow to- 
wards the apex, where, decussating the longitudinal striz, they 
present small folds or punctate-looking bosses ; interstitial spaces 
smooth, auricles large, unequal. 
~ This shell approaches nearest in ornamentation to the P. retiferus 
of the Great Oolite, but it has a much larger number of concentric 
eostee and is much more delicately marked than that shell. 
Only one perfect example is known; but fragments of several 
others show that it is not an uncommon shell. 
Loc. Wollumbilla. 
23; PECTEN soctaLis, sp.n. Pl. XI. fig. 9. 
Shell suborbicular, moderately convex; umbones convex and 
pointed, auricles large, unequal, anterior one much the largest. 
The external ornamentation of this shell is not well preserved ; 
but it appears to have been nearly smooth, without visible concen- 
tric striz, but with depressed radiating ribs. In general form it 
is not unlike P. rigidus. It is one of the most abundant shells in 
the boulders from Wollumbilla, many specimens of all ages appearing 
on their fractured surfaces. 
Loc. Wollumbilla. 
24, PECTEN GREENOUGHIENSIS, sp.n. Pl. XI. fig. 10. 
Shell small, ovately orbicular, auricles oblique, narrow, unequal ; 
surface with very numerous, close, slightly waving coste, about 
forty-eight in number, which are crossed by very fine regular con- 
centric striz, which give the shell an ornate aspect. 
From the Greenough district, Western Australia. 
25. Prcren FIMBRIATUS, sp.n. Pl. XI. fig. 8. 
Shell rather convex, with numerous longitudinal slightly nodu- 
lated costee at the front of the shell, and continuing to about the 
middle, where they die out, are faint intermediate striz. These are 
