15 



not denudation scooped away the beds in the direction, of 

 Cornelian Bay Cemetery we could trace the clays as they 

 dipped under the basalt at Cornelian Bay Cemetery Bluff. 

 (See Plate No. 4<.J 



The basalt sheets at Cornelian Bay Cemetery are soft, 

 vesicular, and sometimes disposed in hexagonal columns in the 

 exposed vertical faces. There is scarcely any doubt but 

 that the similar sheets, at a short distance across the estuary, 

 (i.e., at Beauty and Lindisfarne Bays), were at a recent period 

 connected. It is also probable that the soft vesicular masses 

 at Cornelian Bay bear the same relation to the more dense 

 and crystalline sheet overlying the travertin at Geilston as the 

 dense and porous sheets at One Tree Point already described. 

 The basaltic sheets to the north and west of Prince of Wales' 

 Bay are also mostly vesicular. Most frequently the cavities 

 are filled with lime, and are thus converted into true 

 amygdaloids. 



The best illustration of the extent of the pebbly drifts 

 overlying the basalts may be seen at Lindisfarne Bay on the 

 seaward margin of His Honor Mr. Justice Dobson's property, 

 of which No. 5 is a sketch. (See Plate No. 5. J 



The water- worn pebble beds are sometimes of considerable 

 thickness. The pebbles have been derived from various 

 sources : — Fossil pines silicified from the coal measure sand- 

 stones, fossiliferous water-worn blocks from the palaeozoic 

 mudslones, water worn boulders of diabase of secondary 

 age, feldspathic basalt from the underlying rock, and 

 fossilized trunks of a well-known exogenous tree of tertiary 

 age, evidently silicified m situ. The appearance of the 

 latter wood, rough, angular, not worn, presents a marked 

 contrast when compared with the polished water- worn 

 silicified pines and other pebbles from the older rocks. The 

 sections of the fossil wood of tertiary age under the micro- 

 scope appear to be identical in every respect with similar 

 sections obtained by me from kindred deposits near Little 

 Badger Corner, Flinders' Island, and also at Corra Lynn, 

 Launceston. 



SHELL BEDS. 



I have also shown that the pebbly beds occur in the same 

 position relative to the basalt on the opposite western shore, 

 and some of them with the shelly deposits at Cornelian Bay 

 have already received attention. Mr. Wintle, who is a very 

 intelligent observer, has drawn attention to them on several 

 occasions. Some of his interesting observations have 

 already been discussed before the members of this Society. 

 In one of them he has correctly shown that the agates, 

 cornelians, and jaspers, so abundant around the beautiful 



