president's address. 21 



The bottom temperature at 2,100 fathoms was found by the 

 *' Challenger " to be 34'5°. This probably indicates that a body 

 of cold and heavy water, two and a half degrees aljove freezing, 

 here creeps north from the Antarctic. 



Looking backwards, I remind you that the Society now 

 celebrates its thirty-fifth anniversary, and that twenty-five of 

 such Meetings have been held in this Hall. During this exist- 

 ence we hope that not only have we advanced abstract science, 

 but that we have also done the State some service in economic 

 science. Looking forward, I conclude with the Presidential 

 Amen 



Floreat Societas Linneana ! 



EXPLANATION OF PLATES I. -II. 



Plate i. 



Full face view of model of the submarine slope off Sydney from Deewhy on 

 the north to Cronulla on the south twenty-three miles, and extending east by 

 south for sixty-six miles down to two thousand one hundred fathoms. Above 

 is seen the entrance to Port Jackson on the right and to Botany Bay on the 

 left. Tlie cliffs of the coast are roughly expressed as a continuous wall 

 three hundred feet high. Below the cliffs the sea floor is steep and broken, 

 exposures of bare rock prevail. Beyond this again the rough bottom is 

 buried under a nearly level expanse of sand and mud. Here the contour 

 lines are emphasised to show bays opposite the harbour mouths and a cape 

 running out between them . The limit of the continental shelf is determined 

 by the steep slope reached after passing the hundred fathom line. On the 

 right the shelf is carried out further and ends on a more sudden fall than 

 on the left. This is associated with its proximity to the estuary of the 

 Hawkesbury. The focus of the Sydney dykes is marked by a star. Various 

 soundings on the Admiralty chart upon which the contours are calculated 

 are shown by beads at 290, 650, 960, 1100 and 1200 fathoms respectively. 

 The most important are the 960 and 1200 fathoms points on which Mount 

 Woolnough is modelled. About this horizon the boundaries swell in an 

 intermediate curve which may refer to other volcanoes, but is compared 

 with a similar subfold below Ulladulla. The slope below Mt. Woolnough 

 is gentler and continues beyond the area mapped. It is carpeted with 

 globigerina ooze. 



