Reviews—Der Baw der Erde. 379 
boiling over took place outwards in both directions. The Pyrenees, 
Alps, Carpathians, and Balkans, and perhaps the Caucasus form 
the northern limb, thrust northwards, while the Atlas, Apennines, 
Dinaric chains, Taurus and Iranian arc form the southern limb, thrust 
southwards. The connexion between the Atlas and Betic Cordillera 
at the Straits of Gibraltar is abandoned, and both chains are con- 
sidered to run out into the Atlantic, towards the Azores and Antilles. 
Another unorthodox view is that the Appalachians are the direct 
continuation of the Caledonian chains of Norway and Scotland. 
For this little evidence is given, and we note here a tendency that 
prevails among nearly all writers on this subject, namely, to mix up 
mountain ranges of quite different ages, if only the directions 
coincide. 
The general structure of all the principal mountain chains and 
of the continental blocks of the world is considered in more or less 
detail. It is impossible here to discuss the many interesting 
points raised. It must suffice to say that the author finally comes to 
the conclusion that the present plan of the earth consists of solid 
continental blocks, each surrounded by an orogenic ring; these 
blocks are eight in number, two of them being now submerged 
beneath the Pacific ; the rest form the existing continents, Hurasia, 
Africa, Indo-Australia, North America, South America, and 
Antarctica. These continental blocks form an octahedron whose 
edges are the orogenic geosynclinals, and of which two of the corners 
are situated, one in the Azores, at the crossing of the Mediterranean 
geosynclinal and the central ridge of the Atlantic, which is regarded 
as another principal orogenic zone, and the other somewhere in the 
Sunda Archipelago. The point in the Azores is the apex of the land- 
pyramid, the other the apex of the water pyramid, or hemisphere, 
which together form the octahedron. All this is very nicely worked 
out, and then, finally, in the last two pages, the author seems strongly 
inclined to go back on himself and to pin his faith to the old tetra- 
hedral theory of Lowthian Green. 
With regard to the prime cause of earth-movements in general, 
and mountain building in particular, the theory of isostasy in its 
prevailing form is rejected, everything being referred to simple 
contraction of the earth, and attention is directed to the great 
diminution in the size of the earth, which must have accompanied 
the folding and compression of originally horizontal strata. It is 
calculated that the reduction of the earth’s radius since the beginning 
of Paleozoic times must have amounted to several hundred miles. 
Whatever opinion we may hold as to the value of the ideas set 
forth and the conclusions drawn, there can be no doubt that the 
book is very well written and will be of considerable value as a 
summary of the ideas now prevailing among continental geologists 
on this subject. 
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