CONTINENTAL SHELF. — DANNEVIG. 341 



kSouthwards fi-oni Gabo Island the «helf widens out con- 

 siderably, and consists entirely of the outer or deeper strata, 

 which, between 50 and 800 fathoms, is miles wide. The 

 edge gradually bends westwards parallel with the coast until 

 opposite the mouth of the Snowy Riv^er, where at a distance 

 of about thirty miles from land it turns abruptly to the south. 

 On approaching the bond the shallow area (of less than 50 

 fathoms) has gradually extended at the expense of the outer 

 ledge, and while the former continues westward through 

 Bass Strait and connects Victoria and Tasmania, the latter 

 extends as a relatively narrow belt along the eastern slope 

 past Flinders Island and along the east coast of Tasmania. 



The bottom conditions south and west from Gabo Island 

 are similar to what has been described on the east coast ; 

 the shallow section is either rough or covered with coarse 

 sand, while the deeper ledge is covered with fine deposits. 

 The outer edge, however, is occasionally rocky and the 

 contour rather irregular. South from Cape Everard in par- 

 ticular has been located a deep indentation presenting abrupt 

 and sharp margins. This also is the case to the east from 

 the Sisters Islands and at a place further south, where pro- 

 nounced irregularities have been located and where rocks 

 protrude. 



"J'he survey work of the " Endeavour," as will be seen, has- 

 furnished a considerable amount of additional data in refer- 

 ence to the Continental Shelf of the East Coast, and while it 

 remains for the expert geologist to exj)lain, if possible, the 

 peculiar conditions mentioned, it may here be of interest to 

 summarise the seemingly most important features. 



The tendency to subdivision into an inner and outer 

 section can hardly be accidental, but will probably be found 

 to be due to one or all of the three following causes — currents,, 

 wave action, and elevation or depression of the Continent. 

 The work of the " Endeavour " has furnished a considerable 

 amount of data since the shelf was last discussed, and it is 

 of intei'est in the light of the additional information to review 

 the situation. After discussing two cross sections of the shelf,^ 

 one oft' Sydney and the other off Ulladulla, or about one 

 hundred miles further south, Mr. C. Hedley^ came to the 

 conclusion that the shelf is being produced by eroded matter 

 from the coast being carried seawards and tipped over the 

 outer edge by the current ; he concludes that as in the two 

 cases examined Ijy him the outer edge must be soft and more 

 or less elevated above a solid foundation. The case, how- 



1. Hedley, C — The Subinarine Slope of New South Wales — Proc. Linn. 

 Soc. N.S. Wales., xxxv., 1910, pp. 12-17, pis. i. & ii. 



