634 THE TORSION-STRUCTURE OF THE DOLOMITES. [Aug. 1 899, 



account should be taken of the original inequalities of the sea-floor, 

 which might find a parallel in the tropical Pacific. The tuflfs of the 

 district could not all belong to the Tertiary era ; on this point the 

 evidence of contemporaneous Triassic corals seemed conclusive. 



Prof. Watts pointed out that, among the rocks submitted to him, 

 there were some undoubted tuffs, some augite-porphyrites and 

 labradorite-porphy rites, the constituents of which occurred in the 

 tufifs, and one example of a rock which appears to be related to 

 liebenerite-porphyrites. 



Dr. J. W. Gregory expressed his congratulations to the Author 

 on the brilliant results attained by the combined application of 

 stratigraphy and palaeontology. He doubted whether the coral-reef 

 theory would have been proposed had any detailed study of the 

 corals been then made. The resemblances between the dolomites in 

 the Eastern and Western Alps was of much interest : in the latter 

 area the principal Triassic dolomite-mass was similarly isolated by 

 faults and intersected by thrust-planes, and the reef-corals described 

 from it were of Upper Mesozoic age and had been let down into the 

 dolomites by trough-faults. With reference to the age of the volcanic 

 rocks, it had been proved in the Cottians that they belonged to more 

 than one age. Along the great bow of the Western Alps there were 

 outcrops of massive igneous rocks in positions analogous to those 

 along the Judicarian line, and the speaker had endeavoured to show 

 that they were later than the Middle Kainozoic. 



Prof. Lapworth pointed out that the Author recognized the 

 existence of contemporaneous igneous rocks and tuffs in the 

 Buchenstein-Cassian succession of Triassic age ; but she claimed 

 that the igneous rocks occurring in the fault-lines were intrusive, 

 and were of Tertiary date. This paper was the result of several 

 seasons of hard field-work in a critical area of the Dolomite country, 

 by one who had previously made herself familiar with all the 

 stratigraphical zones. He was himself prepared to accept her 

 description of the complex folding and faulting in the area covered 

 by her work in the field ; and he looked upon her map and sections 

 of that area as a most important and suggestive contribution to our 

 knowledge of Alpine stratigraphy. 



