18 



NOTES ON THE POSSIBLE OSCILLATION OF 



LEVELS OF LAND AND SEA IN TASMANIA 



DUEING EECENT TEAES. 



By Captain Shoett, E.N. 



Duriug the years 1883, 1884, 1885, andl886, or immediately 

 prior to the eruption at Tarawera, this island, and the South- 

 Eastern portion of the mainland of Australia, were frequently- 

 shaken by earth tremors ; and as such disturbances are often 

 known to be associated with local changes of sea and land, it 

 appeared to me to be of great importance to ascertain whether 

 any recent change could be traced along the coast-line of this 

 island. 



This enquiry in a young colony is attended with many 

 difficulties, as with one isolated exception, hereafter discussed, 

 no definitely fixed tide marks are in existence by which satis- 

 factory conclusion might be drawn. 



The exception, however, is of peculiar interest, as it affords 

 us some information, so far as the locality is concerned, in 

 which this fixed tide mark occurs. The tide mark here referred 

 to is situated on the North side of the " Isle of the Dead," 

 which lies ofi" Point Puer, Port Arthur. This mark was cut 

 in the rock broad arrow form, on the 1st July, 1841, by the 

 then Deputy-Assistant Commissary- General, Mr. Lempriere. 

 The circumstances under which this mark was placed there is 

 explained by Captain Sir James Clark Eoss, E.N., in his work 

 entitled " A Voyage of Discovery and Eesearch in the Southern 

 and Antarctic Eegions during the years 1839-43." Thus Page 

 22 : — My principal object in visiting Port Arthur was to afford a 

 comparison of our standard barometer with that which had 

 been supplied to Mr. Lempriere, the Dupty- Assistant Com- 

 missary- G-eneral, in accordance with my instructions ; and also 

 to establish a permanent mark at the zero point, or general 

 mean level of the sea, as determined by the tidal observations 

 which Mr. Lempriere had conducted with perseverance and 

 exactness for some time ; by which means any secular variation 

 in the relative level of the land and sea, which is known to 

 occur on some coasts, might at any future period be detected, 

 and its amount determined. The point chosen for this purpose 

 was the perpendicular cliff of the small islet off Point Puer, 

 which being near to the tide register, rendered the operation 

 more simple and exact ; the Governor, Sir John Pranklin, whom 

 I had accompanied on an official visit to the settlement, gave 

 directions to afford Mr. Lempriere every assistance of labourers 



