Schaw. — On the Last Glacial Epoch. 519 



shore during a period of refrigeration, and by the subsequent 

 raising of the shore to its present height of 40ft. above sea- 

 level. This seems to be a reasonable explanation of the record 

 of ice-action on a low shore in lat. 36° S. In this paper Mr. 

 Johnston gives a mass of very interesting and valuable informa- 

 tion relative to glacier-action amongst the Australian Alps 

 in lat. 36° 30' S. Mount Kosciusko and iis neighbours, over 

 7,000ft. high, show evidences of former glaciers, but at high 

 levels only. This corresponds with similar evidence in Colo- 

 rado and New Mexico, in North America, where the moun- 

 tains are 14,000ft. high, and formerly had extensive glaciers, 

 reaching to about the 5,000ft. level. 



In Tasmania he gives additional facts corresponding with 

 those mentioned in Mr. Dunn's paper, showing that in recent 

 geological times there were extensive glaciers in the western 

 highlands of Tasmania, where the mountains are from 4,000ft. 

 to 5,000ft. high ; but there is no evidence that they reached 

 the sea, although they have left their marks in the river-beds 

 and on the low-lying land. 



Mr. Johnston is disposed to assign a more remote antiquity 

 to these indications than is Mr. Dunn, but Mr. Johnston is 

 evidently influenced by the astronomical theory of Dr. Croll, 

 and it does not appear to me that he brings any evidence to 

 support this view, which would refer the indications of glacier- 

 action in Australia and Tasmania, where no glaciers now exist, 

 to 80,000 or 100,000 years ago, instead of 8,000 or 10,000 

 years ago as in the Northern Hemisphere. 



If we inquire what were the circumstances of those parts 

 of the earth which were affected by it during the ice age, we 

 find these circumstances must have been very various. The 

 most common evidences of ice-action are moraines, or the col- 

 lection of boulders and stony material confusedly piled to- 

 gether, and often scratched and polished ; erratic blocks far 

 removed from their parent rocks ; groovings, planings, and 

 roundings-off and polishing of rocks in situ ; in some places 

 deep beds of tough clay mixed with scratched and rubbed 

 stones, known as " till," in others " kettleholes " or deep 

 hollows in the ground; long lines of deposited stones and 

 other material, like the beds of streams, only raised in relief 

 above the surrounding surface ; and many such strange evi- 

 dences of a mighty power at work, quite different from the 

 ordinary work done by rains, and streams, and rivers, and 

 seas, or by volcanic agency. In many instances the work has 

 evidently been done by glaciers, as it is precisely similar to 

 that now being carried on by existing glaciers ; but where such 

 evidences are found at a great distance from mountains — on 

 the plains of America, Canada, central Europe, and in Eng- 

 land — we are constrained to seek for some agency different 



