December 19, 1901] 



NA TURE 



147 



are widely distributed in Central Asia, and it is practically 

 certain that they are not all of the same age ; thus 

 Zeiller has recognised affinities with the Gondwana flora 

 and has referred certain deposits occurring in the Altai 

 Mountains to the Permian period. From a consideration 

 of these plant-bearing deposits the author is led to an 

 interesting generalisation. They indicate a Mesozoic 

 continent on the north comparable with Gondwanaland 

 on the south. Between the two lay Neumayr's Centrale 

 Mittelmeer (the author's Tethys), the marine deposits of 

 which are now traceable in a broad zone stretching from 

 Timor and Sumatra through Tonkin, Yunnan, the Hima- 

 laya, Pamir and Hindu Kush to Asia Minor and Europe. 

 Modem Asia owes its origin, therefore, in great measure, 

 to the disappearance of Tethys, the rucking up of its 

 sediments into mighty mountain ranges and the con- 

 sequent union of .Angaraland on the north with the 

 Indian fragment of Gondwanaland on the south. 



The third element which enters into the structure of 

 the east Siberian tableland consists of Mesozoic marine 

 deposits, indicating encroachments of the sea from the 

 north at various periods. They have not as yet been 

 traced further south than 62' N. lat., but as the plant- 

 bearing beds of the Angara series have been found in 

 higher latitudes it is certain that the northern boundary 

 of Angaraland must have oscillated backwards and 

 forwards during the Mesozoic period. The marine 

 deposits include representatives of the Middle Lias, 

 Oxfordian, the Volga series and the Neocomian. 



The fourth element consists of widespread sheets of 

 basaltic lava. One of these sheets extends from latitude 

 60° 15' on the Lower Tunguska to the mouth of the 

 Yenesei. It covers about 6^ of latitude and 9" of longi- 

 tude. These basalts do not stand related to definite 

 volcanic cones. They are of the true plateau type and 

 are thus brought into connection with the basalts of 

 Franz Josef Land and of the Brito-Icelandic province. 



On the Lower Tunguska they are associated with 

 deposits of the .Angara series, and, although true lavas 

 occur, it is not improbable that the sediments were in- 

 vaded and sometimes broken up by vast intrusions of a 

 sill-like character, which separated and floated off' large 

 ■ masses. 



The third section of the work deals with the old nucleus 

 (der alte Scheitel). This extends from the Yenesei 

 above Krasnoyarsk eastwards to the Great Chingan 

 range and as far south as the Gobi Altai. East of Lake 

 Baikal the dominant strike is south-west or west- 

 south-west, west of Lake Baikal it is south-east or east- 

 south-east. These two dominant strikes were produced 

 by pre-Cambrian earth-stresses, but they have deter- 

 mined the directions of the later folding and faulting on 

 the borders of the amphitheatre of Irkutsk and in other 

 regions. 



In addition to granites, gneisses and schists, the only 

 rocks entering into the composition of the area in question 

 are fresh-water Tertiary formations and basalts — the latter 

 are allied to those occurring m the tableland of east 

 Siberia. The period of eruptions must have been of great 

 duration, for basalt is found, not only capping the ancient 

 hills of gneiss and schist in horizontal sheets, but occurs 

 also in the beds of existing valleys. The district has 

 been broken up into " horsts '' and " sinkings," which are 

 NO. 1677, VOL. 65] 



described in great detail from the writings of Russian 

 geologists. Many of the " sinkings " are shown to be of 

 the rift-valley type (Griiben). 



The fourth section treats of the Great Chingan range, 

 the plain of the Upper Amur, the Aldan mountains, the 

 Lesser Chingan, Manchuria, Sichoto-Alin, Hokkaido, 

 Sachalin and the Japanese islands. Over the whole 

 of this vast area the author recognises a common type 

 of structure. We will give his views as nearly as possible 

 in his own words. 



" In the fruitful plain of the Amur, through the dark 

 primeval forests oftheTurkana mountamsand the Lesser 

 Chingan as far as the deserts of Sachalin and the great 

 oceanic depths off the Japanese coast, a common arrange- 

 ment of the leading lines (Leitlinien)finds expression in the 

 convergence of all the curved mountain ranges towards the 

 north of the Sea of Okhotsk. . , . Could we remove the 

 waters of the ocean we should then see the curved rows 

 of islands standing out as mighty mountain ranges. 

 Curve follows curve (Bogen reiht sich an Bogen), and the 

 wonderful agency by which all these curved chains have 

 been produced appears to have proceeded outwards from 

 the central nucleus and to have extended its operations 

 beyond the limits of the modern coast-line." 



As the Pacific Ocean is approached, marine deposits of 

 Mesozoic age are met with and traces of the Middle 

 Cretaceous transgression are found in the island of 

 Sachalin. But the plant-bearing beds of the Angara 

 series occur in the plain of the Amur and in Manchuria, 

 thus indicating an e.xtension of Angaraland which has 

 been dropped down in successive steps towards the east 

 by faults and flexures. In spite of this, however, the 

 land area must have increased where the marine Mesozoic 

 strata occur. This increase may have been caused in 

 part by folding, but is probably due, in the main, to a 

 draining off" of the sea-waters to fill oceanic depressions 

 formed elsewhere. 



Angaraland, which in some parts of Asia goes back to 

 the Carboniferous and in others at least to the Rhastic 

 periods, furnishes an illustration of the permanence of 

 continental areas, though not in the sense in which that 

 expression is usually employed. Since life first appeared 

 on the planet, the phylogenetic thread has never been 

 broken, although evolution has not been continuous and 

 uniform. For the dwellers on the land and in fresh- 

 water the continuity of this thread requires the per- 

 manence of continental areas for long periods. Angara- 

 land must, therefore, have been of great importance from 

 a biological point of view. Throughout a large portion 

 of geological time it must have been, not only a retreat 

 for terrestrial and fresh-water forms of life, but also a 

 land capable of sending out colonists as occasions arose. 



Enough has now been said to give an idea of the 

 nature of the book and of the method of treatment 

 adopted by the author. The contents of the remaining 

 sections will only be indicated. The fifth and sixth deal 

 with the Altai and the more or less related chains which 

 the author groups under the name of the Altaides ; the 

 seventh with the Yarkand-arc and with Iran and Turan ; 

 the eighth with the principal ranges of Asia Minor ; the 

 ninth and last treats of northern Europe. 



Geologists may differ on many points discussed by the 



I author, but no one can complain of the way in which he 



has presented his views. He is never dogmatic. His 



