ON COLLECTING IN ANTARCTIC 



SEAS. 



By T. V. Hodgson, F.L.S. 



As the stay of the ' Discovery ' in Winter Quarters extended over two years, it may 

 be of some interest to explain the principal features and conditions of the locality 

 where such a large proportion of the collections were made. 



McMurdo Sound, as it now appears on the charts, is the channel passing between 

 the mainland of South Victoria Land and the large island upon which the active 

 volcanoes Erebus and Terror stand. The Sound is, however, converted into a true 

 bay by the passage across its southern extremity of that vast sheet of ice which forms 

 Eoss' Great Ice Barrier, and which as effectively closes it as if by terra firma. As this 

 great ice sheet travels northwards past the Sound, pressure is relieved and the ice 

 invades the bay, but its action is checked and complicated by means of certain islands 

 as shown on the map issued with Vols. I. and II. Of these. White Island is the most 

 important, as it lies nearly half-way between Minna Bluff and Cape Mackay, 

 dividing the southern opening of the Sound into two. The larger and more easterly 

 of the two openings is by far the most important, as the other is complicated by 

 the presence of Black Island. Brown Island exerts but little influence on the ice 

 movements of the Sound. 



A tide crack separating the Barrier from the " floating " ice runs between Black 

 Island and the Bluff Eange a little to the south of Mount Discovery. From the 

 south-west corner of Black Island there is a continuous if gradual rise in the ice-sheet 

 to a line between the south-east corner of the same island and White Island. From 

 this point there is a comparatively rapid descent possibly equal to, if not greater than, 

 the previous ascent ; the descent is accomplished in the distance of half a mile, and 

 there is a triple tide crack at the bottom. The mouth of the Sound from Cape Bird 

 to an unnamed headland on the mainland is about forty-two geographical miles 

 wide, and it is approximately the same distance from Cape Bird to Hut Point, under 

 the shelter of which the ' Discovery ' lay. These figures were given to me by 

 Lieut. Armitage when we were in Winter Quarters. Subsequent observations, as 

 shown by the map, seem to have modified them a little. 



On the 20th of January, 1902, the 'Discovery' passed across the mouth of 

 McMurdo Sound ; it was then full of ice. The floes were of no great size and for the 



VOL. III. B 



