BY K. ETIIERIDGE, JUXK. 535 



lip gently receding inwards, except at quite the anterior, where 

 il is sharp and prominent ; outer lip not preserved ; mouth 

 apparently round oval. Band narrow in proportion to the size of 

 the shell, but probably in the perfect shell prominent ; sinus not 

 preserved. 



Obs. — The specimen is both at the same time an internal cast 

 and a decorticated shell, weathering having removed every trace of 

 sculpture, lea^dng only a faint indication of the band. The shelly 

 covering remaining exhibits the weatherworn, almost eroded 

 and cracked appearance characteristic of the Yatton fossils. The 

 outer lip is quite imperfect, and as regards the band it is 

 decipherable to the eye in front on the third whorl as a dark line, 

 and to the touch as an obstructing ridge. On the body whorl, 

 and on the third just below the suture the surface is depressed, 

 either flattened or slightly concave. 



I should have referred this shell to Plev,rnf.omarla rotunda, 

 Etheridge,* from Crocow Creek, had it not been for the following 

 reasons : — 1. In the latter the whorls appear to be wholly rounded, 

 without any flattened surface below the suture ; 2. the great 

 relative disproportion in size between the second whorls of the 

 two shells ; 3. the more oblique inner lip in Pti/chomjihalina ; 

 \. the more depressed outline in l\ rotunda, and consequently 

 fliflierent apical angle. 



The present fossil by the position of the band and want of an 

 umbilicus falls within Bayle's genus Ptychomjihalina ( Ptychom- 

 pJidluf', De Kon., non Ag.), and is akin to /"*. gigas, De Kon., 

 in size, although it is larger. 



Named in honour of Mr. W. H. Rands, Assistant Government 

 Geologist, Queensland. 



Loc. and Horizon. — Yatton Gold-field ( ir. //. Bands, Colin. 

 Geological Survey Queensland, Brisbane). Gympie Series. 



* Quart. Journ. Geol. Soc, 1S7'2, xxviii. p. 336, t. 18, f. 3. The generic 

 position of tliis fossil is somewhat doubtful. In his original description 

 Mr. Etheiidge leaves the question of an umbilicus in doubt. From tlie 

 appearance of the type figure the shell appears to be non-umbilicate, l)ut 

 its general features and absence of any band induced me to refer it to 

 P/nfyschisma, McCoy. In the description of Plate 15 of the Queensland 

 Geology and Palaeontology this is called rotundata. It should be rotunda. 



