156 Van Diemens Land, paet i. 



different parts of the whole island; from the same 

 authority, I may add, that on the north-eastern coast and 

 in Bass' Straits primary rocks extensively occur. 



The shores of Storm Bay are skirted, to the height 

 of a few hundred feet, by strata of sandstone, contain- 

 ing pebbles of the formation just described, with its 

 characteristic fossils, and therefore belonging to a sub- 

 sequent age. These strata of sandstone often pass into 

 shale, and alternate with layers of impure coal; they 

 have in many places been violently disturbed. Near 

 Hobart Town, I observed one dike, nearly a hundred 

 yards in width, on one side of which the strata were 

 tilted at an angle of 60°, and on the other they were 

 in some parts vertical, and had been altered by the 

 effects of the heat. On the west side of Storm Bay, I 

 found these strata capped by streams of basaltic lava 

 with olivine ; and close by there was a mass of brecci- 

 ated scoria?, containing pebbles of lava, which probably 

 marks the place of an ancient submarine crater. Two 

 of these streams of basalt were separated from each 

 other by a layer of argillaceous wacke, which could be 

 traced passing into partially altered scorias. The 

 wacke contained numerous rounded grains of a soft, 

 grass-green mineral, with a waxy lustre, and translu- 

 cent on its edges : under the blowpipe it instantly 

 blackened, and the points fused into a strongly magnetic, 

 black enamel. In these characters, it resembles those 

 masses of decomposed olivine, described at St. Jago in 

 the Cape de Verde group ; and I should have thought 

 that it had thus originated, had I not found a similar 

 substance, in cylindrical threads, within the cells of the 

 vesicular basalt, — a state under which olivine never 

 appears ; this substance, 1 I believe, would be classed as 

 bole by mineralogists. 



1 Chlorophaeite, described by Dr. MacCulloch (' Western Islands,' 



