The new material on which this paper is based has lately been received through Mr. D. Ferguson, who recently investigated the geology of the island, and collected the rocks described in an earlier paper. It consists of twenty-seven rock specimens from the south-eastern end of the island, between Cape Disappointment and Cooper Island, and nine specimens from Gold Harbour on the north-east coast between Cooper Island and Royal Bay. All these were collected by the staff of the South Georgia Co., Ltd., under the instructions of Mr. Th. E. Salvesen, managing director, of Leith.