350 "ENDEAVOUR" SCIENTIFIC RESULTS. 



It will be seen that the general meeting ground between 

 these two main tide waves is about the middle of the Strait, 

 approximately between Low Head in Tasmania and Cape 

 Schanck in Victoria. It should here be observed that while 

 the western flood inclines towards Victoria and enters the 

 northern section of the common meeting ground, the eastern 

 stream approaches the southern portion of the same neutral 

 ground, only from the opposite direction. Wherever these 

 streams reach this centre their waters are gradually forced 

 into a rotary movement, the direction being from we-;t 

 through north and east, or against the sun. 



When later on the tide has ebbed sufficiently back through 

 the channels by which it entered, the li mound " of water in 

 the central area will simply flatten out ; no rotary movement 

 in the reverse direction has so far been observed in connection 

 with the ebb. 



While the tidal streams come and go from east and west, 

 there are other causes which independently affect the water 

 circulation. The normal current within the eastern approaches 

 to Bass Strait flows from north-east to south-west and south. 

 It provides the waters which by the eastern flood tide was 

 pushed into the nearest section of the Strait, and in return 

 picks up the ebb tide and presses it southwards along the 

 east coast of Tasmania. In its southward passage the east 

 coast current may be said to sway to and fro at the mouth 

 of the Strait and without making any effort to penetrate the 

 Straits to any appreciable extent. 



To the west from the Strait, however, the conditions are 

 different. Here a current from the Southern Ocean presses 

 against the southern coast of Victoria and King Island, and 

 although its greater volume is diverted to south-east and 

 south long before reaching land sufficient force remains to 

 establish a general " drift " through the Strait from west to 

 east. This current is in the open ocean accentuated by the 

 dominating westerly winds, and as this wind direction prevails 

 in the Strait to the extent of about 16,000 miles per annum 

 (Melbourne Observatory) its influence will make itself felt 

 also upon the local waters. Another factor of some conse- 

 quence is the powerful wave action associated with the 

 prevailing winds which materially assist in distributing the 

 deposits. 



Ihe circumstances here related have left their mark upon 

 the physiography of the Straits in many respects. 



Nature of the Bottom, Elevations and Depressions of the 

 Bottom. As previously stated, the shelf to the west from 



