24 
marked sculpture may be accepted as features distiup;uisliing our shell ; in 
addition, the carinm in M. pUcata arc decidedly sharper and more prominent. 
The specihc name is derived from the locality. 
Log. — 'Well, Dunlop Holding, Darling- Diver, North-West X. S. Wales, 
at a depth of three hundred and eighty-eight feet {C. S. Willdnson) ; Momha 
Head Station, Momha Holding, Darling lliver ( R. Tate), in the same district. 
Ilor. — Lower Cretaceous. 
Log. — AVhite Clilfs Opal-field, near AVilcannia, North-'West N. S. 
AVales {JFarden W. G. 3IaGkenzie F. G. de F. Glpps). 
Ilor. — Upper Cretaceous ("Wliite Clitfs Opal Scries). 
Colin. — Mining and Geological Museum, Sydney ; late Prof. II. Tate, 
Adelaide ; and Gipps. 
^loDioLA Tatei, Etli. fil. 
(PI. I, Fis. 11.) 
Ilodiola Tatei, Eth. fil., IVlem. E. Soc. S. Austr., in Hit. 
Ohs. — A- small example of this species, composed of common opal, was 
collected by Mr. P. G. de '\^. Gipps at the "White Cliffs Opal-field. The outline 
of the shell is elongately mytiloid, and the valves are slightly displaced. 
The anterior ends are small and projecting, and the posterior diagonal ridges 
obtusely rounded, but disajipearing before the posterior margins are reached. 
The unibones are inconspicuous and depressed, and the ventral margins 
straight. Obscure concentric lamina? of growth are visible, but no radii. 
Log. — 'White Clitfs Opal-field {F. G. de F. Gipps). 
Ilor . — Upper Cretaceous (White Cliffs Opal Series). 
Colin. — Gipps. 
^loDiOLA, sp. ind. 
fPl. I, Figs. 12 and 13.) 
Ohs. — A small form of Modiola that it is impossible to name specifi- 
cally. It is elongately pod-shaped with small jirojecting anterior ends, but 
without other determinate characters. It is converted into common opal. 
This little shell may be the young oi 31. dunlopensis, mihi. 
Log. — 'White Cliffs Opal-ficld [F. G. de F. Gipps). 
Ilor. — Upper Cretaceous CV^Tiitc Cliffs Opal Series), 
Colin. — Gipps. 
