^40 Charles Fenner : 



The Croydon sunkland worked out on physiographic evidence 

 by Jutson (ref. 33) has its locality suggested by a line, K, in the 

 north-eastern corner of Fig 5. Regarding Selwyn's fault, it may 

 be mentioned as of physiographic interest, that where the line cuts 

 across, the granite mass of Arthur's Seat, it has left a straight and 

 ^•lean-cut boundary for some two miles, and in the resistant granite 

 this face has been wonderfully well preserved (see Military Survey's 

 .Sorrento Sheet). 



Mr. Chapman's evidence (ref. 8) from the famous Sorrento bore, 

 shows a down-throw to the west of over 1700 feet. In a letter re- 

 garding the palaeontological evidence of the Sorrento bore (on the 

 down-throw side of Selwyn's fault), Mr. Chapman writes : — " I 

 think that here we have perhaps the oldest piece of evidence of 

 Kainozoic faulting, which may date back to the Oligocene, for in 

 no other way can I see an explanation of the great thickness of sedi- 

 ments of Balcombian age in the Sorrento bore, which maintains a 

 fairly equable bathymetric- aspect throughout. And here the 

 movement probably continued till Pleistocene times, and the area 

 may be subject to fits of weakness and collapse even at the present 

 'day." The fault is shown in section. Fig. 12, as the eastern 

 boundary of the Port Phillip sunkland. 



(b) Faults near Geelong. — Dr. Hall (ref. 28) mentions an east- 

 west fault bounding the northern face of the soft Jurassic mud- 

 stones of the Barrabool Hills (see g, Fig. 5). At right angles to 

 this fault there are apparently two other short ones, with a high 

 ^•idge (horst) between. Dr. Summers and others have made investi- 

 irations concerning these faults, and the evidence is generally 

 accepted as conclusive; nothing as far as known to the writer has 

 Deei. published concerning them (except ref. 28). That to the west 

 is commonly referred to as the Orphanage hill fault, and runs 

 through near the cement works, meeting the Barrabool hills fault 

 About Queen's Park, and forming the triangular *' let-down " 

 basalt plain between the junction of the Barwon and the Moorabool. 

 The eastern one (Fig. 5) is believed to be marked by a low scarp 

 that runs nearly north-south through Lovely Banks. This line is 

 very clearly delineated on Quarter Sheets 19 S.E., 24 N.E., and 

 •24 S.E., and is about fifteen miles long. (See also ref. 46.) 



(v.) Suf/gested Fault. — We may be permitted to leave the domain 

 ■of more or less demonstrated fact, in order to indicate a line that 

 suggests itself as being a significant structural feature in the 

 physiographic evolution of this area. It will be referred to as 

 the Doran-Egerton line. 



