SILURIAN BIVALVED MOLLUSCA OF VICTORIA. 
Family Conocardiide. 
Genus ConocarpiuM, Brown, 1835. 
Conocardium bellulum, Cresswell, sp. 
Pleurorhynchus bellulus, Cresswell, 1893, Proc. Roy. Soe. 
Vict., Vol. V., N.S. p. 43, Pl. IX., Fig. 6. 
Observations.—This species is distinguished from the 
rarer form which accompanies it, by the more numerous coste, 
which are typically lamellated or even squamose, by the greater 
obliquity of the umbonal ridge, and by its generally smaller 
size. 
Affinities —The nearest described form to C. bellulum is 
Salter’s species C. dipterum* from the Upper Ordovician (Bala 
beds) of Ayrshire, Scotland. In this species, however, the 
umbonal ridge and the costz are not so oblique nor so strongly 
curved. 
C’. bellulum also shows some alliance with Conocardium 
cuneus, Conrad sp. var. nasuta, J. Hall,t a fossil which occurs 
in the Helderberg series of New York State. 
Horizon and Locality.—Silurian (Yeringian). The type 
specimen was found by the Rev. A. W. Cresswell at Cave Hill, 
Lilydale. It is also an abundant species in the dark-blue lime- 
stone of Deep Creek, a tributary of the Thomson River, Gipps- 
land, 7 miles N. of Walhalla. Specimens from the latter locality 
were presented to the National Museum by Mr. Cresswell. In 
the Geol. Surv. Coll. from the junction of the Woori Yallock and 
Yarra, B 23, we have a single specimen in mudstone, which 
is also referable to the above species. [911 (type), 2343-51, 
7932. | 
Conocardium costatum, Cresswell sp. 
Pleurorhynchus costatus, Cresswell, 1893, Proc. R. Soc., 
Vic., Vol. V. N.S., p. 43, Pl. IX., Fig. 5. 
Horizon and Locality.—Silurian (Melbournian); a slightly 
crushed and otherwise imperfect specimen from the Domain- 
road sewer is here doubtfully referred to the above species.— 
Presented by Mr. F. P. Spry. 
Silurian (Yeringian). The type specimen came from Cave 
Hill, Lilydale, and there is also another specimen from the same 
locality in the National Museum collection. {910 (type), 1086, 
7931. } 
*In Murchison’s Siluria, 1859, 3rd ed., p. 214, Fossils 36, Fig. 7 (Pleurorhynchus 
dipterus). ; 
+ Pal. N. York, Vol. V., Pt. I., 1885, Lamell, II., p. 410, Pl. LXVII., Figs. 12-20. 
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