Geology of Hobavt Town. 133 



A third route lies in the direction of Clarence, and 

 towards Frederick Henry Bay ; the geological features re- 

 sembling those of the last-mentioned district. On a line, 

 in the direction of Sandy Point Bay, also, the rocks differed 

 but little from those of the two preceding, only that nume- 

 rous erratic blocks of limestone were scattered about the 

 roadside, showing that the formation was probably at the 

 surface at no great distance. 



In a series of branching tracks leading up the gullies of 

 Mount Wellington, probably in consequence of convulsive 

 movements, the limestone is met with, within a mile of the 

 boundary of Hobart Town. 



Eobart Town itself is situate on undulating ground, 

 rising gradually from the sea towards the north-west. Two 

 valleys traverse the area in a longitudinal direction. On the 

 western side, a hill named Knocklofty forms a considerable 

 elevation ; and still further in the same direction, Mount 

 Wellington rises to a height of more than 4,000 feet. 



On a map geologically coloured it will be seen, that the 

 site of Hobart Town is composed of a number of broad and 

 alternate stripes of sandstone and basalt, such stripes running 

 parallel with the valleys previously alluded to. 



It is worthy of remark, that the whole of the sandstones 

 have a dip in the direction of Mount Wellington. This 

 peculiarity is, save on the sides of the mountain itself, 

 pretty general over the whole adjacent district. On the 

 sides of Mount Wellington the dip is in a directly opposite 

 direction. 



In a section drawn from the Derwent to the top of Mount 

 Wellington, the arrangement of the sandstones resembles a 

 series of ratchet teeth, rising one above the other towards 

 the south-west. As a very homely illustration, we may 

 suppose a set of wooden cubes to be laid out upon a yielding 

 foundation, say a sofa cushion, so that the surface of the 

 whole represents a perfectly level superficies. Anon, and 

 some disturbing force changes the horizontal plane of each 

 cube into a gently sloping incline, and forms at every joint 

 a diminutive escarpment. If we can only imagine that some 

 molten substance, such as wax, has been forced through the 

 various interstices from beneath, so that its overflow par- 

 tially fills up the miniature valleys, we shall have a model 

 representation of Hobart Town with its sandstones, disloca- 

 tions, and eruptive rocks. 



It will probably be asked why the dip of the various 





