NATURE 



145 



THURSDAY, DECEMBER 19, i9o>- 



THE FACE OF THE EARTH. 



Das Antlil- der Eriie. Yon Eduard Suess. Mit 23 Text- 

 abbildungen, 6 Tafeln und einer Karte der Scheitel 

 Eurasien's. Dritter Band. Erste Hiilfte. Pp. iv + 

 508. (Wien : Tempsky, 1901.) Price 255-. net. 



La Face de la Terre. Par Eduard Suess. Traduit avec 

 autorisation de I'Auteur et Annote sous la Direction de 

 Emmanuel de Margdrie. Tome II. Pp. 87S. (Paris : 

 Colin, 1900.) 



SINCE the publication of Lyell's "Principles" no 

 general treatise on geology has aroused more in- 

 terest or exercised a more important influence on the 

 evolution of geological ideas than '■ Das Anllitz der Erde," 

 the first two volumes of which were reviewed in N.\TURE 

 of .April 25, 1889. Thirteen years have elapsed since the 

 second volume appeared. It left the plot — if we may be 

 allowed to use that expression — in a somewhat compli- 

 cated condition, but the interest was maintained and not 

 a little curiosity was aroused as to how the distinguished 

 author would weave the various threads together. The 

 first part of the last volume is now before us, but the 

 mystery is not solved. We must wait with such patience 

 as we can command until the conclusion appears. 



As the leading ideas which run through the entire work 

 may not be familiar to all readers of N.\ture, a brief 

 account of them will be given before proceeding to the 

 review of the new volume. It must, however, be remem- 

 bered that the work contains a careful and elaborate 

 statement of facts relating to the structure of almost 

 every part of the world, and is, therefore, of great value 

 as a work of reference, quite apart from the truth or 

 error of the theoretical views of the author. 



A study of the structure of the earth's crust proves that 

 it has been affected by two types of movement — the one 

 characterised by a compression of the stratified rocks 

 along certain zones, the other by a separation of the crust 

 into blocks, some of which have sunk down relatively to 

 others. The first type is best illustrated in modern 

 mountain ranges, such as the Alps and Himalayas, the 

 second in districts which have not recently been affected 

 by folding movements. 



One and the same area cannot be simultaneously 

 affected by these two types of movement, but a folded 

 zone may, after the folding stresses have ceased to act, be 

 broken up by more or less vertical faults and by the 

 sinking down of certain portions. It is probable that no 

 part of the earth's surface has escaped the action of 

 lateral pressure, but large tracts — as, for example, the 

 north of Russia— have not been affected by it since pre- 

 Cambrian times. 



By the sinking of certain areas ocean basins are 

 formed, enlarged or deepened, and terrestrial features 

 like the Great Rift Valley of Central Africa are produced. 

 When the sinking process takes place those parts of the 

 crust which remain stationary, or which do not sink so 

 much as the others, are termed "horsts." According to 

 the author, the continents are of the nature of " horsts " ; 

 they have not been formed by elevation, but by the sink- 

 ing of the intervening tracts. 



NO. 167;. VOL. 65] 



In support of such a view he refers especially to the 

 fact that no proofs of the presence of a Mesozoic sea are 

 to be found over southern India or the corresponding 

 portion of Africa. On the contrary, the continental de- 

 posits of the Gondwana and Karoo series end off abruptly 

 against the ocean. Such facts as these are, he considers, 

 incompatible with the view that continents have been 

 formed by elevation. 



But although the existing oceans have been formed 

 by depressions, it must not be supposed that all parts 

 of any one ocean are of the same age, any more than that 

 he continents have been formed by one simple or con- 

 tinuous process. The modern Atlantic, for example, has 

 probably been produced by an enlargement in a northern 

 and southern direction of Neumayr's Centrale Mittelmeer. 



The geologist, however, has not only to deal with 

 movements of the earth's crust, but also with changes in 

 the relative level of land and sea. In speaking of such 

 movements Prof Suess considers that we should adopt 

 a phraseology independent of theory. A rise of sea-level 

 he terms a positive movement and a sinking of the sea-level 

 a negative movement. The Black Sea and the .-Egean 

 Sea are both of quite recent date. If no water occupied 

 these areas before the sinking took place, a lowering of 

 the sea-level all the world over to the extent of about four 

 metres must have been produced when they were formed. 

 The crust of the earth breaks in and the sea follows ; 

 but whilst the depressions of the lithosphere are limited 

 in extent the lowering of the sea-level is universal. 



If we study the succession and distribution of sedimen- 

 tary deposits we find, over large areas, clear evidence of 

 transgressions or, in other words, of positive movements ; 

 these must have been of great extent and duration. 

 Comparative stratigraphy shows that the positive and 

 negative movements are too widely extended to be due 

 to local movements of elevation and depression affecting 

 the solid crust. Thus the Upper Cretaceous transgression, 

 which forms such a striking feature in the geology of 

 southern England, makes itself felt on the Amazon, on 

 the Athabaska and on the Elbe, on the banks of the Nile 

 and in the Tarim Basin, in the valley of the Narbudda 

 and in Borneo, in the island of Sachalin and on the 

 banks of the Sacramento. 



The very fact that we are able to employ the same 

 terminology to distinguish the broader sedimentary groups 

 in all parts of the world is a proof that the limits of these 

 groups have been determined by general and not by local 

 causes. England is peculiarly well adapted to furnish 

 the basis for a general classification, because the more 

 important negative movements are here clearly marked 

 out by the intercalation, in the marine series, of contin- 

 ental or fresh-water formations ; and the limits established 

 by William Smith and his successors correspond, for the 

 most part, to these movements. At the commencement 

 of a negative phase portions of the oceanic areas become 

 isolated, saline and gypsiferous deposits are formed and 

 the marine fauna becomes impoverished, but its final dis- 

 appearance only takes place after the negative phase has 

 reached its maximum. 



It must not be supposed that the movements are con- 

 tinuous. Just as the actual limit of the water is continually 

 oscillating backwards and forwards during the rise and 

 fall of the tide, so it is with the positive and negative 



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