72 Shephard, ^ Visit to Great Lake, Tasmania, [voil'^xxxiii. 



Carboniferous rocks, has left small islets, which, owing to the 

 jointing of the strata, are of square outline. Here is the well- 

 known " natural pavement." The geological speculation in 

 regard to this is that an intruded sill has metamorphosed the 

 sandstone when the igneous rock was stih hot, and thus 

 induced the joints, which break up the rock into blocks of very 

 regular shape. 



A walk southward over a mile or two of wide sandy beach 

 brings one to the southern extremity of the bay, where the 

 "Blow-hole" is situated. A tongue of land, projecting north- 

 ward, forms a natural breakwater ; it is composed' of fossiliferous 

 Permo-Carboniferous rocks, dipping westward, and thus 

 presenting a vertical cliff seaward. This cliff is made up of 

 hard and soft layers, and the unceasing action of the waves 

 attacks the lower soft layers, and, entering along joints, makes 

 tunnels, which come to the surface, owing to the land sloping 

 down from the edge of the cliff inland. This Blow-hole is not 

 an isolated phenomenon, but is a stage in the process of 

 denudation going on for some distance along this coast -line. 

 Tasman's Arch and the open rifts are later developments of a 

 blow-hole. 



Another excursion of interest is to follow the Derwent up 

 stream to New Norfolk and thence by the valley of the Russell 

 River to the Russell Falls, near the foot of Mount Field, which, 

 on the occasion of this visit, was capped with snow. It is 

 interesting to know that a considerable area in this district 

 is to be reserved as a national park. 



Returning to the subject of Great Lake. Proceeding by 

 road from Hobart, the Derwent is followed for twelve miles 

 to Bridge water, where the crossing is made by the long bridge. 

 Passing Pontville, Bagdad, and Kempton, the main road is 

 followed to Melton Mowbray, where a turn westward is made 

 into a narrow but good road, passing through Apsley, the rail- 

 way terminus, and rising until Bothwell is gained, about fifty 

 miles from Hobart. An altitude of about 2,000 feet is attained 

 here. Proceeding, the country becomes very solitary and the 

 landscape assumes a wild and somewhat forbidding aspect, 

 the change in the appearance of the vegetation being obvious 

 even to the non-botanical eye. At a place named ^The Steppes, 

 where only one solitary cottage is to be seen, some fourteen 

 miles from Great Lake, the level of the plateau is practically 

 reached, only moderate undulations occurring. The altitude is 

 here about 3,300 feet, Init fair-sized eucalypts are to be seen, 

 though not numerous. A very noticeable feature is the great 

 growth of lichen which covers the blocks of diabase and basalt 

 which lie everywhere on the surface, the dead timber strewn 

 about, even the living heath plants, being covered with it. 



