PLATE XII. 
Aviriilo])ec-ten, s]>. 
Fig. 1. Kiglit \alve of an Aviculoj^ecfen allied to .1. Spreii/i, on the surface of a weathered 
slab of polyzoal shale. 
Deltopecten sul)([uin(juelineatus, McGojj, .sp. 
Fig. 2. Testiferoii.s left vahe, with the juiinary, secondary, and tertiary costa' di.stinctly ^■isible. 
Fig. .■). Exfoliated light valve of the same specimen (8ce PI. XIV, Fig. 1.) 
Aviculopecten jionderosus, Etli.fil. and Dun. 
Fig. 4. Convex valve of a partly testiferous exam})le. 
Aviculopecten Alitchelli, Etli.fd. and Bun. 
Fig. b. Internal cast of a right valve, with the wide liyssal sinus dividing off the anterior 
auricle. 
Localities. 
Fig. 1. Near Cessnock. 
Figs. 2, .3. Gerringong. 
Fig. 4. Portion 97, Parish Milfield, County Durham. 
Fig. -5. Reservoir, West Alaitland. 
