May 31, 1917] 



NATURE 



■73 



central range, the Allardyce Mountains, is capped by 

 perpetual snowfields, which feed numerous icefields and 

 glaciers, some of which enter the sea, while others 

 almost reach it, as is shown by Mr. Ferguson's photo- 

 graph of Cumberland Bay (Fig. i). Numerous 

 spurs project north-westward from the central range 

 and. the coast is indented by an elaborate series of 

 fiords and fiards. Mr. Ferguson claims that the 

 scenery is the grandest and most picturesque in the 

 Antarctic Islands of the South Atlantic. He compares it 

 with that of north-western Scotland, and his beautiful 

 photographs illustrate some of the resemblances be- 

 tween them. These arms of the sea form magnificent 

 harbours, which are used by the South Atlantic whal- 

 ing fleet. One of the chief centres, Leith Harbour, 

 is shown in Fig. 2. 



zoic, but that is an unsafe guide. The palaeonto- 

 logical evidence is difficult of interpretation, for the 

 fossils are badly preserved. 



The first fossil was obtained in an erratic block at 

 Moraine Fiord in Cumberland Bay by the Swedish 

 Expedition under Dr. Otto Nordenskjold ; it is a 

 lamellibranch which has been identified as a Mesozoic 

 Posidonomya. Dr. Konig, of the German Antarctic 

 Expedition under Lieut. Filchner, found an ammonite 

 in the mi<?dle part of the Cumberland Bay series r 

 Prof. Pompeckj says that it may be an Acanthoceras, 

 and, if so, is Cretaceous. Some cherts, which were 

 collected by Mr. Ferguson at Cape Pariadin, the south 

 point at the extreme north-west end of the island, 

 contain radiolaria. They have been examined by Dr. 

 Hinde, who regards their age as probably between; 



F'G. 2. — Leith Harbour, Stromness Bay. Whale Oil and Guano Works. South Georgia Co., Ltd. Fro:a the i rans. Roy. Soc. Edinburgh. 



The island is mainly composed of sedimentar\' 

 rocks, which have been much folded and faulted. At 

 the south-eastern end of the island is an area of 

 igneous rocks, amongst which Mr. Tyrrell has identi- 

 fied granite-porphyry, alaskite, quartz-trachyte, and 

 felsite, and a sill of diabase occurs beside Cumberland 

 Bay. Mr. Fergusoa's field of work lav chieflv among 

 the sedimentary rocks, which include phyllites, slates, 

 mudstones, graywackes, cherts, and tr'achytic tuffs. 

 Their composition is throughout generally similar, 

 though the lowest rocks are the most altered and dis- 

 turbed. Mr. Ferguson clasafies the rocks into two 

 divisions, a lower, or Cape George, series, and an 

 Uf^er, or Cumberland Bay, series. Thev are together 

 more than 6000 ft. in thickness. The evidence as to 

 the age of these ro<;ks is conflicting. Their litho- 

 logical character at first suggests that thev are Palcco- 

 NO. 2483, VOL. 99] 



the Tricissic and the Cretaceous ; but their evidence- 

 is inconclusive, and Dr. Hinde remarks that this view 

 might be modified by further knowledge of these 

 radiolaria. 



The Middle Cumberland Bay series therefore ap- 

 pears to be Mesozoic ; but the fossils obtained from 

 the Lower Cumberland Bay series in the promontory' 

 between Leith Harbour and Nansen Harbour, near 

 the middle of the north-eastern coast, appear much 

 older. The fossils are so crushed that their identifi- 

 cation is only put forward tentatively. One of them 

 appears to be a tabulate coral resembling Omphyma. 

 It is associated with some fucoids which resemble 

 Buthotrefhis succulens from the Trenton Limestone 

 of New York, and with some branched fossils referred' 

 to Camarocladia, which occur with Buthotrephis in the 

 Trenton Limestone of Illinois. The fossils have been 



