602 



NATURE 



[April 25, 1889 



author now passes to South Africa, the Indian peninsula, 

 and Madagascar, which have the characters of a table- 

 land which was once continuous, and from their geological 

 history the sediments are dei'ived which constitute the 

 Cretaceous and Tertiary rocks of the Sahara and Arabia. 

 The high land to the north of India is fully described, 

 chain by chain, in the details of geological structure which 

 govern their forms and continuity, leading to the volcanic 

 regions of Java and Sumatra. There appear to be four 

 great curves southward, seen in the Iranian chain, 

 Hindu Kush, Himalayas, and the Malayan chain. 

 The connection between the mountains of Central Asia 

 and Europe is traced on the basis of the distribution of 

 Tertiary strata : all the European mountains are regarded 

 as continuations of chains which extend from the Thian 

 Shan group. The continuity here sought to be established 

 would appear to depend not less on the evidence of 

 denudation than upon stratigraphical proofs of con- 

 temporary folding. The author, for example, carries the 

 line of Cyprus through Crete into the Dinaric Alps, while 

 the chain of the Caucasus passes through the Crimea and | 

 Balkans by Ovsovainto the Carpathians ; but these curved j 

 lines seem to us rather the results of denudation of folded 

 rocks than an indication of the directions in which the 

 lines of folding were prolonged. 



Three chapters are devoted to North and South 

 America and the West Indies, treating ot the rock- 

 structure and folding of the earth-rind in the same way 

 as in other parts of the globe. The rind appears to the 

 author as more plastic or more symmetrically bent than 

 Ave have been accustomed to regard it, insomuch that he 

 -everywhere finds the chains curved, whereas we often 

 find them extending at angles to each other. The vol- 

 canoes of the West Indies are found to have the same 

 relation to the main chain as have those of the Apennines 

 and Carpathians, being on the inner side of the arch. 

 And the Caribbean Sea is further compared with the 

 western part of the Mediterranean. 



The second volume is devoted to the oceans, and com- I 

 mences with an historical account of views held by sue- : 

 cessive investigators on the displacement of the shore-line. I 

 Three lines of investigation suggest themselves : first, the j 

 changing distribution of the seas in successive periods of 

 time, which may be furnished by evidence of shore-lines 

 and sea-margins ; secondly, by comparing the areas of 

 deposition of sediments in past time, some idea is ob- 

 tained of the ancient oceans ; and thirdly, by studying 

 existing shores, evidence is found of oscillations in level. 

 Beginning with the great waters of the present time, a 

 detailed history is given of the Atlantic. Its shores are 

 described, especially in the northern regions, and the 

 mountains which extend towards the European coast 

 are traced, and said to be paralleled by chains on the 

 •other side of the Atlantic, so that the old rocks of Ireland, 

 Cornwall, and Brittany, appear to extend beneath the 

 ocean. The west coast of Africa, and shores of Central 

 and South America, are similarly described and com- 

 pared in the light of their geological structure. The 

 Serro do Mar in South America is regarded as com- 

 parable with the Appalachian chain, and hence it follows 

 that the entire American continent is the consequence of 

 a tangential thrust towards the Pacific Ocean. The history 

 of the Pacific Ocean begins' with the shores of New 



Zealand and Australia, but the author avails himself of 

 the fossil floras and other evidences to indicate ancient 

 relations of the strata with the corresponding rocks of 

 Europe, India, and other localities. The fine is followed 

 on through New Ireland, New Caledonia, Borneo, Cochin 

 China, Tonquin, the Philippines, and Japan, and so by 

 the Kurile and Aleutian Islands to the west coast ot 

 America, everywhere dwelling on the light thrown by tlic 

 geological structure of those countries upon the variations 

 in extension of the sea. The Atlantic and Pacific are 

 compared with each other, and found to have many points 

 of structure in common. The foregoing evidences of 

 change in ancient oceans furnished by the rocks seen on 

 their borders, necessitate a history of geological changes 

 in the Palaeozoic, Mesozoic, and Tertiary periods of time. 

 In a chapter on Palaeozoic oceans, it is stated that they 

 make us aware of two continents which now only remain 

 in fragments. The first occupied the North Atlantic 

 Ocean, furnished the ancient sediments of Europe and 

 America, and its remains persist as Greenland. The 

 second continent is first recognizable at the end of the 

 Carboniferous period. Its relics persist in Africa, India, 

 and Australia, As the former is known as Atlantis, so 

 the latter is named Gondwanaland. No seas of the 

 Mesozoic period have left sediments which indicate great 

 depth of water. The chalk alone may be evidence of a 

 deep ocean, which stretched from Europe towards the 

 West Indies in a yet earlier time. Towards the close of 

 the Cretaceous period the seas became smaller. In 

 North America the prairie lands from Canada to Texas 

 and Alabama emerged from the water, and similar ii] 

 heaval is seen in Europe, and especially evidenced in ti. 

 freshwater strata of the Pyrenees and Southern France, 

 which make a transition from the Cretaceous to the Ter- 

 tiary, like that shown by the Purbeck beds in early strata. 



These earliest shallow conditions in Tertiary Europe 

 were succeeded by a central sea which reached far to the 

 east, and is estimated to have spread from London to 

 Khartoum, and from Kiew to the Indian Ocean. And 

 the author sketches with a bold hand the succession of 

 physical conditions changing the breadths of water which 

 have resulted in the contours of existing shore-lines in 

 America and the Old World. 



Evidences of the changes which have occurred in the 

 contour of existing shores are found in detailed study of 

 the coasts of Norway, and the inland terraces, which 

 mark earlier extent of the sea and glacial action. Other 

 evidences of instability of the shore-line are recorded 

 with similar detail on the coasts of Italy. And the his- 

 tory of the Baltic and North Sea emphasize the mutability 

 of shores. The historical records of the Mediterranean 

 shores supply, especially in its eastern parts, striking 

 proofs of oscillation in Greece, Syria, Egypt, and Asia 

 Minor. The northern shores of the world supply many 

 proofs that at the close of the Glacial period the shore- 

 Hne was more elevated than it is now. An examination 

 of the shores of the equatorial and southern seas demon- 

 strates the former wide spread of deposits in which the 

 life is substantially the same as in the nearest oceans, 

 though there is sometimes, as in South America, a larger 

 number of European species. 



Finally, a summary is given of the characteristics and 

 geological history of the oceans which have been de- 



