NEW SIBERIAN ISLANDS are situated off the Arctic coast of Siberia, from 73° to 76° 6' N., and 135° 3o' to 151° E. The name is loosely applied, covering either the northern group only of these islands, for which the name of New Siberian or Anjou Islands ought properly to be reserved, or the southern group as well, which ought to retain its name of Lyakhov Islands. Some confusion prevails also as to whether the islands Bennett, Jokhov, Vilkitski, Henrietta and Jeannette, ought to be included in the same archipelago, or described separately as the Jeannette or De Long Islands. The first three of these belong geographically, and probably geologically to the New Siberian group, from which they are less than ioo m. distant. Henrietta and Jeannette Islands lie 200 m. north-east of Novaya Sibir Island, in 157° to 159° E. Sannikov Land, reported by J. Sannikov in 1805 to lie north of Kotelni Island, probably does not exist. The islands form part of the Yakutsk Soviet Republic.
The New Siberian Islands consist of Kotelni, the largest (116 m. long, ioo m. wide), having the small island Byelkovski near its western shore; Thaddeus (Faddeevski), in the middle; and Novaya Sibir, New Siberia, in the east (90 m. long, 4o m. wide). Kotelni is the largest and reaches an altitude of 1,200 ft. in the volcanic Malakatyn-tas mountain. It is built of Silurian coral limestones (Llandovery division), containing a rich fossil fauna. The same Silurian deposits are widely spread on the mainland as far as the Olenek. Middle Devonian limestones and slates are all faulted north-north-west and south-south-east. Triassic slates appear in the south-east. Diabases pierce to Devonian rocks. The eastern portion of the island, named Bunge's Land, is covered with Post-Tertiary deposits. Novaya Sibir Island attains altitudes of 200 to 30o ft. in its western portion. The so-called Wood Mountains, which were supposed to be accumulations of floating wood, are denudations of Miocene deposits containing layers of brown coal with full stems of trees. These Tertiary deposits are characterized by a rich flora and fauna, testifying to a climate once very much warmer. The only representative of tree vegeta tion now is a dwarf willow I in. high.
The Lyakhov Islands consist of Bolshoi, or Blizhni, which is separated by Laptev Strait, 27 m. wide, from Svyatoi Nos of Siberia ; Mali, or Dalni ; and several smaller islands to the west of Mali. Bolshoi too consists of granite protruding from be neath non-fossiliferous deposits. Along its southern coast Baron Toll found immense layers of fossil ice, 7o ft. thick, evidently
relics from the Ice Age, covered by an upper layer of Post-Tertiary deposits containing numbers of perfectly well-preserved mammoth remains, rhinoceros, °vibes, and bones of the horse, reindeer, American stag, antelope, saiga, and even the tiger, associated with relics of forest vegetation. A stem of Alnus fruticosa, 90 ft. high, was found with all its roots and even fruit. Similar deposits of ground ice occur in Vasilievski Island. Basalts and Tertiary brown coal deposits enter into the composition of the southern extremity of Bennett Island; Vilkitski Island is low (5o ft.) and basaltic. Bennett and Henrietta Islands have a few small glaciers. The New Siberian Islands have none.
The climate of these islands is very severe. In 1886 the winter ended only in June, to begin anew in August (May 21, —5.8° F ; Oct. 16, —34.6°). The highest summer temperature was 50°. Flocks of geese and other birds come to the islands in summer. The lemmings are numerous. Reindeer, followed by wolves, come across the ice from Siberia ; the fox and polar bear feed on the lemmings. There is much driftwood. The islands have been long known to Siberian hunters who come for furs and fossil ivory.
A Yakutsk Cossack, named Vaghin, wintered on Bolshoi in 1712, but it was a merchant, Lyakhov, who first described the two greater islands of this group in 1770, and three years later reached on sledges the largest island of the New Siberian group, which he named Kotelni. M. Hedenstrom, accompanied by San nikov, explored the archipelago and published a map of it in 1811. Anjou visited it in 1821-23. A scientific expedition under Dr. A. Bunge (including Baron E. Toll) explored it in 1885-86. Toll revisited it in 1893 with Shileiko, and again in 1900 with F. G. Seeberg in the "Zarya." The Russian hydrographical expedition in "Taimir" and "Vaigach" in 1912 did some surveys in the New Siberian Islands; in 1913 it discovered Vilkitski Island and in 1914, Jokhov Island. The "Maud" in 1924 visited the New Siberian Islands. (See ARCTIC REGIONS.) BIBLIOGRAPHY.-The works of Hedenstrom, F. von Wrangell, and Anjou, Bunge, and Toll in Beitriige zur Kenntniss des russischen Reichs, ate Folge, iii. (1887). Toll in Memoirs (Zapiski) of the St. Petersburg Academy of Sciences, 7th series, xxxvii. (1889), xliii. (1895), and 8th series, ix. (1899), with maps. Geographical Journal, Dec. 1919; Geo graphical Review, July 1925 and H. U. Sverdrup, Tre Aari Isen med Maud (Oslo, 1926). (R. N. R. B.)