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.
Loc. Wollumbilla. It is named after W. P. Gordon, Esq., of Wollumbilla, through whose assistance many of these fossils have been collected.
21. Lima multistriata, sp. n. Pl. XII. fig. 5.
Shell very convex, oblique ; auricles very small ; hinge-border very narrow ; surface with about forty depressed rounded costae, 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. Pecten (?) Aequilineatus, sp. n. Pl. XI. fig. 11.
Shell ovately orbicular, moderately convex ; surface covered with numerous raised divergent longitudinal striae, crossed by about the same number of equally raised concentric costae, which narrow towards the apex, where, decussating the longitudinal striae, 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 costae 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 socialis, 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 concentric striae, 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 costae, about forty- eight in number, which are crossed by very fine regular concentric striae, which give the shell an ornate aspect.
From the Greenough district, Western Australia.
25. Pecten fimbriatus, sp. n. Pl. XI. fig. 8.
Shell rather convex, with numerous longitudinal slightly nodulated costae at the front of the shell, and continuing to about the middle, where they die out, are faint intermediate striae. These are
