BASS STRAIT. — DANNEVIG. 349 



for the ]>i'esent purpose to take the records as they stand. 

 The sections which are foreshortened sugpest that (I) in the 

 central area the bottom is very level and the slopes gentle, 

 and (2) that irregularities are most pronounced in jilaces where 

 the waters are confined and tides strongest. 8uch localities 

 are to the north, west and south from King Island, wheie the 

 flood and ebb tides rush past at two to four knots per hour. 

 This great force is itself sufficient to carry away and displace 

 all portable material, such as silt and fine sand within moderate 

 depths, and the bottom is midulating and rough in those 

 parts. The heavy Southern Ocean rollers coming in from the 

 west contribute also considerably to this disturbance. 



Another rough area is the Banks Strait, where on account 

 of the narrowness of the waters the fiood and ebb tides ruu 

 from four to five knots, and when opposing any sea cause a 

 great commotion that prevents any silting of anything but 

 the heaviest materials, including coarse sand. 



On account of the close relationship between the nature of 

 the bottom and the tides, it is obvious that independent 

 currents will have a similar influence, projiortionate to their 

 strength and continuity, and it has l)een necessary to study 

 the general ^ater circulation within the Strait and immediate 

 surroiuidings in order to obtain an explanation to the present 

 distriliution of the vai'ious deposits — the occurrence of 

 channels, liasins and banks. 



The flood tides enter Bass Strait from four points, viz., 

 north and south past King Island, through Banks Strait, and 

 between the island groups situated letween Flinders Island 

 and Wilfon Promontory. The ebb pours out again through 

 the same channels. Bass Strait is consequently th? meeting 

 place of many waters apart from what rivers discharge into 

 it, and the water circulation is somewhat complex. For the 

 purjaose of simplicity we may first consider the flood tides as 

 entering in the west and east. The former assiune a north- 

 easterly direction on passing King Island, and the northern 

 branch pushes on past Cajje OtAvay toAvards Port Philli]) and 

 Western Port, where small arms enter various inlets. The 

 main body is swayed to the east and south-east toAvards the 

 centre of the Strait and is joined by the southern branch 

 entering between King Island and the Three Hummocks. 



The flood from the east assumes a south-A\-est course ; a 

 small arm folloAvs the Victorian coast Avestward in the direction 

 of Port Phillip, but the main body strikes for the north coast 

 of Tasmania, AA'here it is joined l)y the Avaters coming through 

 Banks Strait. 



