218 F. Chap man: 



and it can be traced up the f7ran<ie Burn to within a short dis- 

 tance of Forsyth's, where it is (jverlain by the nodule bed and 

 the Kalimnan shelly deposits. By the percolation of surface 

 water the limestone has been fretted and excavated into numer- 

 ous "swallow-holes" and caves on the Grange Burn opposite Mr. 

 ITenty's farm, where it perhaps attains its maximum thickness. 



Duncan's original locality for this species is the Tertiaries of 

 the Murray River (loc. supra cit.). Since then the species has 

 been discovered in several localities, but apparently not at 

 Muddy Creek. Messrs. Dennant and KitsonJ- have given the 

 distribution of E. rotundus as follows: — Aire Coast?, Gellibrand 

 River, Glen Aire, Calder River, Maude, Waurn Ponds, Murray 

 River, Spring Creek, to which should now be added Muddy 

 Creek and Grange Burn, near their junction. 



Order — Polyplacophora. 



Family — IscJiuochitonidae. 



Genus — IscJinochiion., Gray. 



Sub-Genus — Isc/uioplax, Carpenter. 



Ischnochiton (Ischnoplax) granulosus, Ashby and 

 Torr sp. 



(PI. XVTTT.. Figs. r)-7). 



Acanthochites (Notoplax) granulosus, Ashby and Torr, 1901, 

 Trans. Roy. Soc, S. Aust., Vol. XXV., p. 139, PI. IV., Fig. 9. 



Observations. — Tbe above species was founded on median 

 valves from the Balcombian clays of Schnapper Point (Bal- 

 combe's Bay, Port Phillip). Curiously, three out of five speci- 

 mens of this fossil in the National Museum collection are tail- 

 valves, and since this part n^ the e.xtcrnid covering has not yet 

 been descrilied, details are now given, with drawings from two of 

 the specimens. 



This species must bo transferred of the genus Ischnochiton, 

 occasioned by the discovery of the tail-valve, particularly charac- 

 terised by a callus-termination oi the posterior border of the 

 articulamentum; and to the sub-genus Ischnoplax, since the shape 



1 Op. cit., p. 132. 



