. N A M. F'g- 5- coarse conglomerate of well-rounded boulders indicating a long period of erosion, suggest that, notwithstanding their freshness, they belong to the older series of lavas. Examination of a series of pebbles from the agglomerate in the vicinity of Martin's Head and Lion's Rump shows that the majority consist of hornblende-augite-andesite lavas and their tuffs. In addition, there is an altered doleritic andesite somewhat similar to that described above, a highly epidotized andesite obviously belonging to the older lava series, and an altered tonalite in which the feldspars have b
. N A M. F'g- 5- coarse conglomerate of well-rounded boulders indicating a long period of erosion, suggest that, notwithstanding their freshness, they belong to the older series of lavas. Examination of a series of pebbles from the agglomerate in the vicinity of Martin's Head and Lion's Rump shows that the majority consist of hornblende-augite-andesite lavas and their tuffs. In addition, there is an altered doleritic andesite somewhat similar to that described above, a highly epidotized andesite obviously belonging to the older lava series, and an altered tonalite in which the feldspars have been thoroughly sericitized and epidotized, and the ferromagnesian minerals chloritized. The hornblende-andesite is an unusual type which has not hitherto been described from West Antarctica. In the best-preserved specimen brownish green pleochroic hornblende in well-shaped crystals comes next to plagioclase in abundance as phenocrysts, and is greatly preponderant over augite. The ground-mass is dense and cryptocrystalline. "nelson island Harmonv Cove. Very little is known about the geology of Nelson Island. Mr Ferguson {op. cit. p. 43) visited Harmony Cove, a harbour at the western corner of the island where Nelson Strait joins Bransfield Strait, and collected a quartz-diorite-porphyry which appeared to be intrusive into an igneous breccia. Dr Mackintosh collected four specimens from Harmony Cove. His account is almost entirely topographical, but he has provided an excellent sketch of the rock exposures (Fig. 5). Study of these specimens confirms Mr Ferguson's results. One of them is a fine-grained norite
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