632 MISS M. M. OGILVIE [mES. GOEDON] ON THE [Aug. 1 899, 



lines, and in a much later geological age folded obliquely to the old 

 lines — cross-folding and crust-contraction having followed longi- 

 tudinal folding and contraction. 



The Judicarian strike in the western area is north-north-east and 

 south-south-west, parallel with the strike of the new folds at Sella ; 

 and the development of this series has been accompanied by the 

 development of a correlated series in a north-north-westerly and 

 south-south-easterly direction (see p. 612), shown in the Trieste 

 strike. Torsion of old anticlines has taken place in these directions, 

 with the development of northern and southern fold-arcs round 

 individual basins. The curve from Schlern to the Sexten Valley 

 describes a northern torsion-arc round the basin of the Dolomites, 

 while the curve from Cima d'Asta to Pieve di Cadore and Auronzo 

 describes a southern torsion-arc round the Dolomites. 



The leading curves of the torsion-system trend from west to 

 south-west and south-south-west in the Adige and Judicarian area, 

 and from east to south-east and south-south-east in the Carinthian 

 and Trieste area. The large sheet of Permian porphyry presents a 

 disturbing element in the course of the torsion-curves, dividing the 

 Adige torsion-basin from the basin of the Dolomites and deflecting 

 the curves round its southern edge. 



The diagram shows at a glance an important general correlation. 

 Short lines in an east-and-west direction have been drawn by the 

 writer to indicate the existence of an older strike, as inferred above 

 and in a former paper. These east-and-west lines are crossed by 

 the torsion-curves at increasingly oblique angles where the curves 

 trend south-westward and south-south-westward, and it is there 

 where Tertiary eruptive activity has been displayed in the Judi- 

 carian region — a region of earlier Permian eruptivity. 



The relation of the peri- Adriatic system of torsion-curves to the 

 torsion-phenomena of the Alps generally cannot be discussed here. 

 In my opinion, the principles of crust-torsion exemplified in the 

 region of the Dolomites can be shown to be equally applicable to 

 the structure of the entire Alpine system. This I propose to deal 

 with elsewhere. 



I cannot conclude without giving expression to a deep feeling of 

 personal indebtedness to the writings of Prof. Suess and Dr. Bittner. 

 The classical works in which the former has traced the great curves 

 of the Alps and its related mountain-systems, taken together with 

 the persistent demonstration by Dr. Bittner of the characteristics 

 of the complicated fault-system in various regions of the Eastern 

 Alps, lead almost inevitably to the conception of crust-torsion on 

 a grand scale. 



I must again gratefully acknowledge my great indebtedness to 

 Baron P. von Richthofen, whose original interpretation of the 

 Triassic succession in the Dolomite country has not only formed 

 the foundation for the researches made by me and all other workers 

 in the same field, but stands to-day undisturbed after forty years 

 of controversy. 



