Tertiary.'] PALJEONTOLOGT OF VICTORIA. IMoUasca. 



and the fine duplicating sulcus of the ridging is well seen, so that 

 at an inch from the beak, in a space of half an inch, 18 to 21 of 

 the smaller striae are to be counted in specimens with well pre- 

 served surfiice, but not more than half that numljer when the 

 outer layer is absent. The nearest analogues of our species are the 

 C. po7iderosa (Hutt) of the New Zealand Tertiary beds of Awatere, 

 and the C. crassatina (Lam.) from the French Upper Eocene, 

 which, however, are much more coarsely ribbed. 



Very common in the Miocene Tertiary sandy beds of Corio Bay 

 (A'' 15) ; very common in similar beds (A* 22 and A* 23) of Bird- 

 Eock Point, 15 miles south of Gcelong, near mouth of S])ring 

 Creek ; also common at Point Addis (A" 24). Piare east of Gelli- 

 brand River (very thick variety) ; not uncommon at Muddy Creek, 

 near Grange Burn, 5 miles from Hamilton ; of large size in 

 Tertiary clays of Mordialloc. Common in Tertiary clays and 

 sands in face of cliff. Dog Island, Leigh River. Rare in Tertiary 

 beds at Bairnsdale, Mitchell River ; presented by A. W. Howitt, 

 Esq. Not uncommon, of large size, in brown sandstone, at the 

 entrance to the Gippsland Lakes. Thin small specimens in 

 Oligocene clays near Mount Martha. 



Explanation of Figures. 



Plate XXVn. — Fig. 3, inner view of small specimen, natural size. Fig. 4, end view of 

 rather small specimen with the two Talves in contact showing the great thickness from one 

 valve to the other, and the form and sulcation nf the cartilage area, natural size. Fig. 5, large 

 specimen showing the normal type with the ohlique form, ohtusely rounded posterior diagonal 

 ridge, and the size and character of the striation, natural size. — (The round hole in the lower 

 part of this specimen was the cause of its death, having heen bcired by the rasp-like tongue of a 

 carnivorous gasteropod of the period.) Fig. 5a, interior of similar specimen, showing the hood- 

 plate slightly broken at the lower end. Fig. 56, striation magnified. 



Frederick McCoy. 



[ 33 ] 



