DESCRIPTION OF THE ISLANDS: BRISTOL I. 177 



At Bristol it is possible to anchor, with good holding ground and protection from 

 wind, anywhere on the northern and eastern sides; but the shape of the island permits 

 the swell to follow round, no matter what its direction may be. South of Grindle and 

 Wilson Rocks there is very deep water, and between them is a basin, apparently en- 

 closed, with depths of over 50 fathoms. This passage is navigable, as is that between 

 Wilson and Freezeland where soundings of not less than 25 fathoms were obtained. 

 Between Grindle Rock and the mainland is a continuous reef with breaking water. 



Bristol Island is deeply covered with glacier, which extends to the coast in every 

 direction (Plate XXV, figs. 1-3) : on the eastern side and to the west of Fryer Point are 

 uninterrupted glacier faces each more than three miles in length. At a number of points 

 the structure of the rock is exposed in steep cliffs, with the glacier hanging above. 

 Measurements were made of the height of the glacier face on the eastern side of the 

 island, and the heights obtained at four points as we moved southwards along the coast 

 were 175, 210, 140 and 260 ft. We think that the average thickness of the ice-covering 

 on all the glaciated islands (Montagu, Bristol, Cook and Thule) may be reckoned at 

 200 ft. 



No steam was seen rising from any part of the island : we are satisfied that all volcanic 

 activity has ceased, and nowhere did we see any indication that the ground still retains 

 warmth. Looking back on the island from the north, on our passage to Montagu, we 

 noticed that the highest parts of the island had the shape of a horse-shoe, suggesting 

 that they once formed part of the rim of a large crater. The appearance is shown, though 

 not very clearly, in Plate XXV, fig. 3. We were not able, however, to come to any definite 

 conclusion on this point: the crater, if it ever was one, must have been very large, with 

 a diameter of about two miles. 



The rocks on Bristol are similar to those on the other islands. At Fryer Point black 

 basaltic lava is to be seen and the rock exposures on the bluff on the south side, at the 

 western headland and in other parts, are of yellowish and red tuff, or tuff conglomerate, 

 sometimes stratified with a grey rock interposed between the layers, but frequently much 

 contorted and with many intrusive dykes. 



From a geological point of view the three large outlying rocks appear to be more 

 interesting than any other place in the entire group of islands (Plate XXV, fig. 4 ; Plate 

 XXVI, figs. 1-4). The great pillar on Freezeland is composed of a pale brown rock of a 

 kind not seen elsewhere. It showed distinct signs of bedding and in the upper part of 

 the column some broad reddish bands. We believe this may be a sedimentary rock. The 

 eastern part of Freezeland, forming the lesser of the two summits, is different; it is 

 formed of a brownish rock, with vertical fissures and striation, and may be meta- 

 morphic. Wilson Rock, nearer the mainland, is a vast mass of black columnar basalt, 

 while Grindle Rock repeats the reddish and yellowish tuffs seen on the adjacent 

 headland of the island. Thus, if our conjectures are correct, the whole succession of 

 rock formations in the Sandwich Group is to be found in these three islets. Freezeland 

 shows the only likely exposure of the underlying sedimentary series that we know to 

 exist, Wilson is of the overlying basalt, here seen in far greater thickness than elsewhere, 



