94 THE GLACIER EPOCH OF AUSTRALASIA, 
(42° South lat.*), in its northern part especially, preserves a 
general rugged or undulating level of about 4,000 feet altitude, 
and its higher bosses and peaks and its valleys do not vary 
much more than 1,000 feet above or below this uniform level. 
From the Picton to Gad’s Hill, a distance northerly of over 
a hundred miles, its westerly hmit may be roughly traced, 
forming a bold and widely undulating margin relative to the 
western country, whose immediate general upland surface 
ranges between 2,000 and 3,000 feet above sea level. This 
margin is markedly broken by the elevated outlying spur 
forming the Eldon Range, near Lake St. Clair. From Gad’s 
Hill in a south easterly direction to the Table Mountain; a 
distance of not less than 90 miles, its similarly indented 
margin presents a still bolder character as it approaches and 
contrasts with the lower fertile plains and valleys of the 
Meander and South Esk, which seldom exceed an altitude of 
from 600 to 700 feet above sea level. 
“ At the great northern and southern water divide, in the 
neighbourhood of the Table Mountain, it suddenly recedes 
and contracts, forming a large bight in the direction of the 
Upper Derwent tributares, notably the rivers Nive and 
Ouse, from which its level tends to fall, and its marginal 
boundaries, though frequently rising into high mountain 
ridges towards Mount Wellington, no longer maintains the 
uniform boldness of outline which characterises its northern 
aspect. . . Nearly everywhere along and agaiust this 
plateau and the greenstone crests of Mount Dromedary, 
Mount Nicholas, Eldon Range, Mount Gell, Grass Tree Hill, 
Constitution Hill, and most of the elevated south-easterm 
dividing ranges, the various members of the Carboniferous 
(Permo-Carboniferous) and Mesozoic rocks are seen to repose 
invariably in a horizontal position, or, at most, with a very 
slight dip towards or away from them.” 
From this description it will be apparent, that, given a 
period of extremely low temperature, the great elevated 
plateau of Tasmania possesses, in a special manner, a great 
width of space at a high level for the formation of an exten- 
sive snowfield. It is also significant that in its present 
western margin, in the vicinity of the mountain valleys, where 
evidences. of former glacial action are so abundantly manifest, 
there is now even the greatest amount of rainfall. This is 
shown by the records at the stations at Corinna, Strahan, and 
Waratah, on the western aspect, as contrasted with the 
records of Great Lake, Ross, Oatlands, and Bothwell, towards 
its eastern limits, as in the following table: — 
*A height of 5,000 feet in this latitude would have an inland temperature of that 
of nearly 6,500 feet altitude in the region of the Australian Alps, 
