of the Island of Tasmania. 1G5 



lower strata. At a bend in the River Tamar, called 

 Stevenson's Bend, there is a very rich deposit of leaf 

 impressions in the banks ; and at Breadalbane Mr. Johnston 

 gives the following section : — Superficial soil, 2 to 3 feet ; 

 basalt, 50 to GO feet ; conglomerate of waterworn fragments 

 of basalt, 3 to 4 feet ; white arenaceous clays, 20 to 30 feet ; 

 lignite, with embedded trunks and branches of pine and 

 other trees, 3 feet. White and grey arenaceous sands of 

 unknown depth. 



From this it would appear that the plant beds denote 

 a flora w T hich existed at the time of some of the volcanic 

 outbursts, but Mr. Johnston is of opinion that the lowest 

 beds rest upon a very old basaltic stratum. My own 

 impression is that the lowest sands are contemporaneous 

 with the older pliocene deposits of Victoria (?) and South 

 Australia, where they are manifested in a similar manner. 

 They rest upon older basalts which cover marine miocene 

 formations, and these may be the basalts which overlie the 

 Table Cape deposits, and which were deposited on the 

 bottom of the miocene sea. 



Close to Hobart, on the south side of the island, tertiary 

 plant remains, with land shells, have been found. They 

 occur in a deposit of travertin in Geilston Bay, on the 

 Derwent River, on the opposite side to Hobart. Abundant 

 leaf impressions, with fossil leaves and wood, have been 

 found in this travertin, with two species of Helix, a Vitrina 

 and a Bulimus. The plant beds have been displaced by a 

 basaltic dyke. The displacement of the stratified beds by 

 the dyke has caused many fissures and cavities, in which 

 the bones of existing animals are lying in abundance. The 

 seeds found in the travertin beds show the deposit to be 

 contemporaneous with the pliocene drifts of Victoria. 



I have now dealt with all the evidence that is known in 

 Tasmania as to physical condition of the island in former 

 geological periods. The question remains to be asked 

 whether we have any evidence that it was formerly united 

 to the Australian continent % There is no geological evidence. 

 It forms a part of the continent geologically, and the space 

 between the two is bridged over by islands. They are of the 

 lowest formations known in Tasmania, covered, in some 

 cases, with miocene and pliocene marine deposits. In the 

 tertiary era, therefore, it is extremely probable that the sea 

 rolled between them, even to a larger extent than it does 

 now. The evidence is in favour of Tasmania, like South- 



