Tertiary Fossils in South Australia. 5 



above, slightly concave beneath. The upper surface studded 

 with small irregularly disposed cells, and the under surface 

 with a calcareous crust, on which are radiating raised 

 ribs and concentric rings. This is a very common fossil, and 

 extends through the whole formation. It is of various sizes, 

 the largest about that of a shilling. The under surface is 

 not unlike a nummulite. 



No. 6. Cellepora tubulosa (Busk). Spherical polyzoaries 

 with one side perforated two-thirds through with a cone- 

 shaped cavity, cells irregular, very large and minute, the 

 latter grouped around the former, and giving an ornamental 

 appearance. 



No. 7. Cellepora spongiosa (Busk). A hard compact irre- 

 gular polyzoary, with cells raised and rounded. Aperture 

 simple. A very common fossil, and never found encrusting 

 others. 



No. 8. Melicerita Angustiloba (Busk). Another species 

 of the genus peculiar to the Crag deposits, dessribed by Milne 

 Edwards. It is a common fossil, and is small and brittle. 



Figures 9 and 10 are two species of Horner a, very common 

 in the beds. They are probably H. Rugulosa, and H. 

 Gambierensis. 



Figure 11 is a fragment of Caber ea lata. It still exists 

 on the coast, and is described in Busk's Catalogue. It is not 

 very common, but occurs from time to time. 



Figure 1 2. Crisia eburnea, I have very little doubt that 

 this is the species described by Johnson (Bri. Zooph., vol. i., 

 p. 284.) It is a British species, .and yet appears to have 

 been very abundant in our seas when these strata were de- 

 posited. The species is not described by Busk, who has 

 distributed Lamouroux's order of Crisidce into o.her genera. 



I have only described in the foregoing a very few of the 

 most common fossils in the Mount Ganibier rocks. It will 

 be seen, even from these few, that most of the species are 

 new. I have omitted mention of three new genera, namely, 

 Psileschara, Cceleschara and Scutularia, of which the leading 

 characteristics are not well made out. But at any rate it 

 will be perceived that these deposits offer a wide field, replete 

 with novelty and interest, and their fauna will probably 

 number thousands of species peculiar to them alone. It 

 must not, however, be supposed that they ever will, even 

 when fully explored, give a true picture of the former state 

 of our seas. More than half the genera and species must 

 have perished. The Polyzoa of our present seas would tell 



