856 Frederick Cluvinnan : 



From the Kalimuaii series (Lower Pliocene) at its base, a fine ex- 

 ample of y. geelonyensis has been collected by Mr. Kurtze, of 

 Hochkirch, which specimen was subsequently presented to the 

 Museum by Mr. C. French, junr. It occurred in a gypsum-bear- 

 ing bed, opposite Mr. Henty's farm, on the Grange Burn, asso- 

 ciated with Ostrea manuhriata and Nation cunninghamensis, and 

 is itself partially filled with selenite. 



Nantihis aUifronn, sp. uov. (Plate V., Figs. 10-12; Plate VI., 

 Fig 13). 



Descri2)tion. — This species is of moderate to large size. It is 

 remarkable for the compressed form of the shell, and its conse- 

 quently high apertural front. The chambers number about 15 to 

 17 in the last whorl. The umbilicus is open and deep, but not of 

 great width; it has the appearance of being stepped, OAving to the 

 compression of the sides of each turn of the shell. The sutures are 

 more undulate than in N . geelongensis, from which it is further 

 distinguished by its depressed form, and almost quadrate aper- 

 ture. Siphuncle sometimes preserved by the infilling of the shell 

 with selenite, when it is seen to be ventral in position. 



Dimensions. — Greatest diameter of type specimen, about 225 

 mm. ; width of umbilicus, 13 mm. ; height of aperture, 124 mm. ; 

 width, 103 mm. 



Affinities. — This form of Nautilus is of the N . urhanus type, of 

 the London Clay, near London, and the I. of Sheppey. In N. 

 urbanns the siphuncle is described by Edwards^- as dor.sal in posi- 

 tion, whilst in the present species, N. altifrofis, as seen in the 

 remarkably fine selenite casts, it is decidedly ventral. 



Occurrence and Horizon. — N . altifrons appears to be restricted 

 to Janjukian strata. It occurs at the Murray River cliffs (type), 

 where it is found preserved in gypsum of the clear variety selenite, 

 which mineral has invaded the chambers, whilst the shelly septa 

 and siphuncle are often well preserved. A cast of this species 

 in white polyzoal limestone from Nor'-west Bend, Murray River, 

 South Australia, is also found in the Museum collection. A cast 

 of Nautilus, probably referable to this species, occurring at Bairne- 

 dale, was presented by Mr. W. A. C. a'Beckett. 



1 "Moil. Eocene CephulaiHida ;ui(i dnivalMs of l';iif,'l.ahd," vol. i. (Pal. Soc), 1841), p. 46. 



