Volcanic Necks at Anderson's Inlet. 173 



may have been bounded in part by steep cliffs composed of Car- 

 boniferous glacial beds, and the climate may have been a 

 rigorous one in winter. By assuming the operation of blown 

 sand under strong winds the conditions would be present for the 

 polishing of any pebbles disintegrated from the subjacent glacial 

 beds. Continued action of blown sand on these pebbles would 

 soon result in them acquiring their high polish. Now, if singly, 

 or in numbers, they fell over the cliffs during the winter, on to 

 the frozen surface of the lake, nothing remained but the floating 

 away of the burdened ice when the thaw set in, and the subse- 

 quent dispersion of the transported pebbles among the sand of 

 the lake bed as the ice of the floes melted away ; or again, the 

 pebbles may have fallen over the cliffs into shallow water, been 

 frozen into ground ice, subsequently floated ofi", and finally 

 dropped when the ice melted. These polished pebbles are found 

 in many parts of the Jurassic system of South Gippsland. Few, 

 however, have such a high polish as have those at Anderson's 

 Inlet. This fact admits of the readier acceptance of the theory, 

 since, assuming ground ice to have been the means of transport,, 

 the whole of the pebbles could hardly have been floated away 

 quickly enough after their fall into the waters of the lake to have 

 prevented their polish from being destroyed, either partially or 

 wholly, by abrasion among the shingle and pebbles of the shore. 



The absence of angular pieces of rock from among these 

 polished pebbles can be explained by the reasonable assumption 

 that the clifts were composed wholly of glacial deposits, and as 

 such they would contain comparatively few small angular pieces. 



Again, the ice transport theory would probably explain the 

 fracturing of the pebbles since they would thus have been sub- 

 jected to great variations of temperature. The occurrence of 

 so many of these fractured pebbles among the Jurassic sediments, 

 as well as in the volcanic necks, is a striking feature. Had they 

 been confined to the necks their fracturing could easily have 

 been accounted for by violent contact witli the material in the 

 old volcanoes. 



A consideration of these matters makes it seem not improbable 

 that both of these agencies — driftwood and floating ice — have 

 operated in the transport of these included pebbles in the Juras- 

 sics. It seems, besides, by no means improbable, that contem- 



