1 7 THE A NT A RCTIC. 



all sides abrupt and steep from the sea to considerable 

 heights, the principal, Mount Foster, to the south-west 

 of the island being in round numbers 6,200 feet high, 

 while Mount Pisco, near the south coast, is estimated to 

 be upwards of 4,250 feet high. Only in one place was 

 a small flat shore found, and on this Weddell was able 

 to land. The whole island is completely covered with 

 ice and snow, with the exception of the steepest slopes 

 where no support exists. Doubtless the strong glaciation 

 of this island, as compared with the other members of the 

 South Shetlands, is accounted for by its elevation, and 

 this theory is borne out by the thicker covering being 

 on the southern side. As to its geological structure we 

 are almost in the dark ; Bellingshausen alone mentions 

 vertical strata, but whether this fact indicates a powerful 

 upheaval of existing strata, or the columnar severance in 

 a surface of volcanic eruptive rock, it is impossible to 

 determine. The latter appears the more probable, be- 

 cause, as already stated, the mere outlines of the island 

 seem to testify to volcanic origin, which would account 

 both for the tilt in the stratification and for its remark- 

 able height. 



We here leave the island chain of the South Shetlands, 

 and turn to the more extensive tracts of land and of island 

 groups lying to their south. 



6. THE DIRK GERRITZ ARCHIPELAGO. 



Of all the tracts of land hitherto discovered in Antarctic 

 regions none in the course of time has afforded so many 

 surprises, nor undergone such fundamental reconstruction 

 on maps and charts as the islands collectively called in 

 modern times the Dirk Gerritz Archipelago. The oldest 

 charts, those of Powell and Weddell, indicate a vaguely 

 outlined coast to the south of the South Shetland Islands,, 



