110 DEVONIAN FOSSILS 
Description. Length 2 em., height 8 mm., and thickness (of 
single valve) 3 mm. Shell rostrate, the umbo being half way 
between the anterior and posterior ends of the valve. Shell convex, 
especially in the umbonal region, but somewhat depressed towards 
the outer margins. Anteriorly broad and well rounded; the mar- 
gin meets the cardinal line at an angle of the order of 160°. 
Posteriorly the height of the shell is much reduced. There is a 
shallow but definite depression down the umbonal slope. At the 
posterior end of the shell, near the cardinal margin, is a sub- 
circular sear about 3 mm. in diameter. Cardinal line arcuate; 
dentition taxodont, teeth large. The beak is depressed so as to 
hide the central part of the cardinal line, but nine teeth can be 
counted on the anterior side of the umbo and ten on the posterior 
side (although the innermost one is small). The steinkern shows 
that the sockets are quadrate on the anterior side of the umbo, but 
on the posterior side they are more elongate and possess a median 
ridge (furrow in the steinkern). 
As shown by the space between the steinkern and external 
mould, the shell was 0-5 mm. thick at the umbo. The fragment of 
external mould shows the ornament to consist of well-marked 
lamellae nearly a millimetre apart; the areas between the lamellae 
have numerous fine striae parallel with the lamellae. 
Comment. The holotype specimen of this species (National 
Museum reg. no. 7,918) had only about one-eighth of an inch of 
the hingeline showing, the original figure being in the nature of a 
reconstruction to a certain extent. The steinkern has now been 
cleared and is re-figured (РІ, III, Fig. 11), but the hingeline 
characters are poorly preserved. The Sandy’s Creek fossil is not 
considered to vary specifically from this type. 
MeLearn (1924, p. 100) referred Chapman’s species to the 
genus T'ancrediopsis. 
Genus COSMOGONIOPHORA MeLearn, 1918 
Cosmogoniophora sp. 
Part of a valve is preserved on specimen 27,226 from locality 
G 24. MeLearn established the genus to include Goniophora 
Species possessing radiating striae. Cosmogoniophora was noted 
to be very common in the Devonian, but in the Silurian confined 
to the Arisaig Stonehouse Formation. Shells with ornament 
similar to the one from Sandy’s Creek occur at Hull Road, 
Mooroolbark. 
