Victorian Fossils, Ft. V. 7 



Ischadites, which has a sub-spherical or pyriform body, often 

 conoaYe at the base. 



A wacx squeeze taken from this fossil cast shows the form 

 of the depressed summit plates, with occasional traces of the 

 diagonal, horizontal, spioular structure. There is also a dis- 

 tinct crenulation on the edges of the summit plates, similar 

 to the fio-ure of the Wenlock specimen of R. ? neptuni Defr., 

 figured by Dr. Hinde.?- 



Measurements. — The present specimen measures 20 mm. in 

 its longest diaimeter, and probably represents about two-thirds 

 of the entire expanse, or a, total diameter of about -30 mm. 

 The rhombic summit plates average 1.5 mm. in their greatest 

 width, and they do not show much variation in size. 



Observations. — R. fergusoni shows certain affinities with R. 

 neptuni, Defranc©,- particularly in the shape of its summit 

 plates and their crenulated margins. It is, however, much 

 smaller than that species, and its conical base not so prolonged. 



Occurrence. — In the yellowish hardened mudstone of Silurian 

 age ; Wombat Creek, a tributary of the Mitta Mitta River, 

 N.E. Gippsland. From the Mines Department; collected by 

 W. H. Ferguson, after whom the fossil is named [2317]. 



The above fossil is associaited with typical Silurian forms be- 

 longing to the genera Euomphalus, Orthis and Atry]Da.'' 



Receptaculites australis, Salter. 

 (PI. I., Figs. 2, 4, 5, 6, 7 ; PI. IT.; PI. TIL, Figs. 2-7). 



Receptaculites australis, Salter, 1859, Canad. Organic Re- 

 mains, Dec. 1, p. 47, pi. X., figs. 8-10. R. Etheridge, junr., and W. 

 S. Dun, 1898, vol. vi., pt. 1, p. 62., pis. viii.-x. 



Observations. — In our Victorian specimens it is the median 

 portion of the sponge wall that is generally seen ; the weather- 

 ing of the fossil producing a regularly papillate surface, owing 

 to the exposure of the ends of the vertical rays or pillars. 



1 Pal. Soc. Mon., vol. xl., 1886 (1887). Brit. Foss. Spoiijjres, pt. i., pi. ii., fiy. :i. 



2 Diet. Sci. Nat., vol. xlv., p. 5, Atlas, pi. Ixviii., fig-, la-d. fSee also G. J. Hinde, loc. 

 supra cit., p. 139, pi. ii., flg. 3, pl. iv., fig. 1. 



3 For the relationship of the fossiliferous beds, see \V. H. Ferguson, in Monthlj' Progress 

 Kep., No. 3, 1899, Geol. Surv. Vict., p. 17. 



