president's address. it 



the continental shelf was here discuvcred by Capt. T. W. 

 Sharp, of ii.M.C.S. "Iris." Eraser's Islanci, Queens-land, 

 terminates to the northward in a prolongation called appro- 

 priately Break-Sea Spit. Nort"li of this, early navigators, 

 among whom were Cook and Flinders, reported water of 

 moderate depth. About 1869 this area was re-surveyed and 

 accurately charted by the British Admiralty. Repairs re- 

 quired by a submarine telegraph cable induced Captain 

 Sharp to re-examine this district in 1904. He found tliat from 

 five to ten miles north of Break- Sea Spit the conformation 

 of the sea-floor had entirely altered during the thirty-four 

 years that had elapsed since the previous survey. Where his 

 predecessors had found from twenty to thirty fathoms he 

 measured from two to three hundred fathoms. The hundred 

 fathom line had greatly changed both in direction and posi- 

 tion. Captain Sharp, who has most kindly su})plied me with 

 this information and the accompanying map (Fig. z!), does 

 not (as I am inclined to do) ascribe the alteration to a move- 

 ment of the earth's crust. He believes it due to excavation 

 of the sea floor by a powerful sovitherly-going current To 

 quote his letter to me, 6/2/ '11, "I consider the bottom in 

 this locality to be liable to variation at any time not by sub- 

 sidence but by currents, as it is entirely sand." 



This change of the sea floor extends over nmre than a 

 hundred square miles. Alterations in the neighbouring coast 

 might have been expected to have accompanied such great 

 changes under the sea. But nothing to correspond has been 

 noticed. Yet Mr. A. Meston refers to an aboriginal tradition 

 that a plateau on Fraser's Island near by siiddenly sank into 

 a large and deep lake.* Mr. W. C. Thomson states that 

 "larire masses of coral arc found inland and near the mouth 

 of the Boyne River [Port Curtis] overlaid by mud."t The 



* Meston, Fiaser'ji Islaml, I'iu liaiiniitar y i;(])<)H.s Qiieeiisland, ]'M)r<, p. 2. 

 t Thomson, (^tieeiislaiul (ieoi^iHiihical .lounial, x.\., 19n5, p. 3. 



2 



