210 SCIENCE PROGRESS 



the major folding is due to magmatic movement. The latter 

 may give rise to large-scale epeirogenic uplift or depression, as 

 in the formation of the Mesozoic sedimentation area, the eastern 

 subsidence at the beginning of the Andean movements, and 

 probably also the vertical uplift of the whole mountain system 

 in quite recent times. The secondary magmatic foci and the 

 enormous lava eruptions may have originated from these 

 batholiths, but they play a passive, not an active, role in the 

 folding. 



In a paper entitled " Die Mediterranen Kettengebirge in 

 Ihrer Beziehung zum Gleichgewichts-Zustand der Erdrinde " 

 (Abk. Sdchs. Akad. Wiss., Matk.~Nat., KL, 38, 1921, 61 pp.) 

 F. Kossmat elaborately discusses the relation between the 

 gravity anomalies and the tectonics of the Mediterranean fold 

 ranges. The main ranges show zones of gravity-defect, as do 

 also the subsided forelands on the outer (N. and N.W.) sides 

 of the Alpine-Carpathian region. The folded chains are not 

 compensated by themselves alone, but in connection with the 

 neighbouring forelands, which are parts of the ranges pressed 

 down by the folding. The interior inbreaks of the Tyrrhenian 

 and Pannonian types are quite different from the forelands, 

 being regions of gravity-excess. The forms of the ranges, the 

 homologies in the courses of the older Eurasian folds, and the 

 arrangement of the major fracture system of the Indo-Gangetic 

 block, show that the fold region is pinched in between stiifer 

 blocks of the earth's crust. The production of differences in 

 regional density distribution is ascribed to tangential move- 

 ments, due to certain rotational and mass actions in which 

 contraction and crustal enlargement by magmatic action appear 

 in competition. Kossmat believes that the obvious connection 

 , of the older and newer Eurasian folds is opposed to Wegener's 

 theory of lateral continental drift. 



Prof. W. H. Hobbs' new book on Earth Evolution and its 

 Facial Expression (New York : The Macmillan Co., 1921, 

 178 pp.), which will be reviewed in a subsequent number, 

 should be noted in connection with the subject of orogeny. 



A most important paper by G. Frodin on " The Analogies 

 between the Scottish and Scandinavian Portions of the Cale- 

 donian Mountain Range " {Bull. Geol. Inst. Upsala, 18, 1922, 

 199-238) institutes a comparison between the composition, 

 structure, and age of the Seve (Are) and Koli Schists of Central 

 Scandinavia, and the Moine and Dalradian of the Scottish 

 Highlands. Tornebohm's original view that the Seve Schists 

 and their folding are Pre-Cambrian is now shown to be un- 

 tenable. The Seve and Koli Schists are now regarded as 

 structural and petrographic facies of Cambro-Silurian rocks, 

 a view supported by continuity with fossiliferous rocks in the 



