DYNAMICAL GEOLOGY. 269 



Pencati had drawn attention to the fact that not far from 

 Predazzo, at the waterfall of Canzacoli, true granite covered 



he Alpine limestone and had altered it to marble. Leopold 



7on Buch doubted in 1821 the position of the granite above 



he limestone, but allowed that the granite had produced the 

 metamorphism of the limestone to marble. Then followed 



3uch's famous papers on dolomite, and on the geology of the 

 Fassa Valley, in which he on the one hand tried to explain the 

 origin of the dolomite by the action of magnesia vapours 

 during the eruption of augite porphyry, and on the other hand 

 associated the upheaval of the Alps with the outbreaks of 

 augite porphyry. 



Buch's declaration that in South Tyrol lay the key to 



he solution of Alpine geology, attracted geologists from all 

 countries to this neighbourhood. The " Triassic granite" and 

 Monzoni syenite, with their wonderful array of contact 

 minerals, the dykes and massive sheets of augite porphyry, 

 melaphyre and liebenerite porphyry, were described by several 

 geologists. In 1824 Poulett-Scrope, Studer, and Ami Boue' 

 visited Predazzo ; in 1843 Von Klipstein published his obser- 

 vations on the Fleims and Fassa Valley; in 1855 the Nor- 

 wegian mineralogist, Kjerulf, published his accurate mineral- 

 ogical and chemical investigation of the Monzoni syenite. 

 Baron von Richthofen's monograph, published in 1860, still 



brms the best foundation for the geology of South Tyrol. 



rle determined a definite succession in the Triassic eruptive 

 rocks first the basic series, augite, porphyrite, monzonite, and 

 hypersthenite, then flows of lava, or the infilling of fissures by 

 tourmaline granite, melaphyre, and liebenerite porphyry. 

 Three years later Bernhardt von Cotta's paper appeared on 

 the intrusions and ramifications of the Monzoni syenite into 

 the limestone, on contact minerals, and on the melaphyre 

 dykes in the limestone and dolomite. Lapparent in 1864 

 sub-divided the eruptive rocks of the neighbourhood into a 

 basic and an acid group, without entering into the particular 

 succession, but Doelter's petrographical studies led him to 

 much the same conclusion about the succession as Richthofen 

 had formed. Reyer, on the other hand, thought that granite 

 and then syenite had been intruded during the Muschelkalk 

 period; monzonite, porphyrite, and andesite had followed; 

 but in his opinion the same eruptive series had been re- 

 peated in various geological epochs. Mojsisovics' work, The 



