iSo 



DISCOVERY REPORTS 



The soundings taken in Douglas Strait, with the approximate positions of the 200, 

 300 and 400 fathom contours, are shown in Fig. 16. It will be seen that deep water 

 extends close up to the eastern and western shores where the coast on both sides is 

 formed of high precipitous cliffs and steeply sloping glacier. The northern entrance to 

 the strait is closed for a great part of its breadth by a reef with sunken rocks extending 

 eastwards from Beach Point. The southern entrance is narrower and lies between the 

 end of the rocks off Reef Point and Twitcher Rock, from which shoal water extends 

 towards Thule Island. 



Observations were made on the plankton and hydrology of this submerged crater at 

 a station situated near the middle of the strait. A sounding with the Lucas machine gave 

 a depth of 358 fathoms (= 655 metres). The bottom sample was of black mud, and its 

 strong smell of sulphuretted hydrogen indicated that the lower layers of water were 

 stagnant. 



Table II. 



The temperatures and salinities are given in Table II, and with them, for comparison, 

 a similar series taken in the open sea between Bellingshausen and Bristol Islands. The 

 latter series shows the conditions which normally prevail in the area, and it will be seen 

 that four distinct layers of water are to be distinguished by temperature. Below the 

 upper layers, warmed by contact with the air, is a cold stratum with a minimum at 55 

 fathoms; beneath this is a warm layer with a maximum at 328 fathoms, while at the 

 bottom cold water is again found. In Douglas Strait the temperatures are quite dif- 



