Eights on the New South Shetlands. 395 



The rocks are composed principally of vertical columns of 

 basalt, resting upon strata of argillaceous conglomerate ; the pil- 

 lars are united in detached groups, having at their bases sloping 

 banks constructed of materials which are constantly accumula- 

 ting by fragments from above. These groups rise abruptly from 

 the irregularly elevated plains, over whose surface they are here 

 and there scattered, presenting an appearance to the eye not 

 unlike some old castle crumbling into ruin, and when situated 

 upon the sandstone promontories that occasionally jut out into 

 the sea, they tower aloft in solitary grandeur over its foaming 

 waves ; sometimes they may be seen piercing the superincum- 

 bent snow, powerfully contrasting their deep murky hues with 

 its spotless purity. Ponds of fresh water are now and then 

 found on the plains, but they do not owe their origin to springs, 

 being formed by the melting of the snow. 



The rocky snores of these islands are formed of bold craggy 

 eminences standing out into the sea at different distances from 

 each other, from whose bases dangerous reefs not ^infrequently 

 lie out for several miles in extent, rendering it necessary for navi- 

 gators to keep a cautious watch, after making any part of this 

 coast: the intervals between these crags are composed of narrow 

 strips of plain, constructed of coarsely angulated fragments of 

 every variety of size, which at some previous period have fallen 

 from the surrounding hills. They slope gradually down to the 

 water terminating in a fine sandy beach : a few rounded pieces 

 of granite are occasionally to be seen lying about, brought un- 

 questionably by the icebergs from their parent hills on some far 

 more southern land, as we saw no rocks of this nature in situ on 

 these islands. In one instance, I obtained a bowlder nearly a 

 foot in diameter from one of these floating hills. The action of 

 the waves has produced little or no effect upon the basalt along 

 this coast, as its angles retain all the acuteness of a recent frac- 

 ture, but where the conglomerate predominates, the masses are 

 generally rounded. 



The color of the basalt is mostly of a greenish black. The 

 prisms have from four to nine sides, most commonly however but 

 six, and are from three to four feet in diameter ; their greatest 

 length in an upright position above the subjacent conglomerate 

 is about eighty feet. Their external surfaces are closely applied 

 to each other, though but slightly united, and consequently they 

 are continually falling out by the expansive power of the congeal- 

 ing water among its fissures. When they are exposed to the 

 influence of the atmosphere for any length of timo, they are for 

 a small depth of a rusty brown color, owing no doubt to the 

 iron which they contain becoming partially peroxydized : some- 

 times they are covered by a thin coating of quartz and chal- 

 cedony. 



