Glaciation of Western Highlands, Tasmania. 135 



of the moraine consist of stones and blocks thrown loosely 

 together, the interstices open ; in other portions, the interstices 

 are filled with fine material. 



Another well marked moraine extends in a southerly direction 

 from Lake Ruby (a small tarn in a gorge under a precipice 280 

 to 300 feet in height) down the course of Limestone Creek. The 

 material, arrangement, etc., are very similar to that of the Lake 

 Rolleston moraine. In both cases the surface of the moraine is 



Erratic Blocks. 



Scattered over the surface all round Lake Dora on the hill 

 sides, and even on the tops of hills 300 feet above the level of that 

 lake, are blocks of stone, from small boulders up to heavy masses 

 many tons in weight, that have been transported, in some cases, 

 for miles by ice from their former sites to their present positions ; 

 all the moi-ainal matter was thus transported. Some of the more 

 conspicuous examples have been especially named on the plan. 

 Scarcely any of them, but if carefully examined, show unmis- 

 takable evidence of having been ground, planed, striated, or 

 polished on some portion of their surfaces. There is a great 

 sameness of material, all of which is local and derived within a 

 very few miles' distance. Some of the large blocks have been 

 split since they reached their present position. Odd blocks of 

 hornblendic rock occur of small size, they probably are derived 

 from masses intruded through the Devonian rocks. Many of the 

 erratic blocks are of great size, and some probably weigh hundreds 

 of tons. 



Planing, Scoring, and Polishing. 



Planed and scored surfaces are features insepai'able from glacial 

 action, and these are most abundantly present over this region. 

 On the western side of Lake Dora the rocky hillocks are planed 

 down, scored, and striated in a beautiful manner, and right up 

 the valley westward from Lake Dora this same action is 

 exemplified on the rounded dome-like rocky projections of schist. 

 To the east of Lake Dora, at the site marked on the plan, there 

 are splendid examples of grooving, etc., both on the sides and 



