242 THE ANTIQUITY OF MAN IN TASMANIA. 



basin is turned in westerly direction, and bears north- 

 north-west-south-south-east. The area of the basin is 

 4,508, say 4,500 square miles. 



A further receding of the water level of 5 fathoms 

 would even lay this lake dry, provided that the level of 

 the inland lake follows that of the open ocean. 



If the level of the inland lake would not follow that 

 of the open ocean we would have the features shown in 

 Fig. 8, PL I., supposing the outer ocean had receded to 

 the 40-fathom level. 



A broad isthmus w^ould connect Tasmania and Aus- 

 tralia. The largest width of this isthmus would be under 

 4odeg. lat., and it would extend from I44deg. long, to 

 about I48deg. 55min. long. ; that is to say, for about 345 

 miles. The east coast of this isthmus would be mono- 

 tonous without deeper bays. The west coast shows, 

 however, a large bay cutting into the land up to I45deg. 

 long., being separated from the inland lake by a narrow 

 and low ridge. South of King Island there are three 

 broad bays. In the centre of the isthmus is a large inland 

 lake, which in the south reaches almost to the present 

 coast of Tasmania, while in the north it is close to the 

 Australian coast. From the eastern ocean this lake is 

 separated by a broad land bridge, whose highest point 

 in Flinders Island is at least 1,400 feet above sea level, 

 while the lowest elevation is not less than 300 feet above 

 sea level. The bridge which separates the lake from the 

 western ocean is, on the whole, somewhat broader than 

 the eastern one, but it is joined to the mainland of Aus- 

 tralia only by a very narrow strip of land hardly raised 

 above sea level. A winding but narrow channel reaches 

 from the west shore close to the Black Pyramid, where 

 again only a narrow strip of land separates it from the 

 open ocean. All the rivers of the north coast, from 

 Montagu River in the west to the Ringarooma in the 

 east, which now discharge their water into Bass Strait, 

 would run into this lake. From Victoria we would have 

 the Snowy and Mitchell Rivers, as well as a number of 

 smaller ones, but Port Phillip would discharge into the 

 open ocean. In all probability this lake would ])e saline, 

 being without an outlet, a fact which is of some im- 

 portance, as we shall see later on. 



