90 HISTORY OF GEOLOGY AND PALEONTOLOGY. 



von Buch and Alexander von Humboldt. During the winter 

 spent by the two friends in Salzburg, they made numerous tours 

 into the Salzkammergut and Gosau Valley. Von Buch's 

 account of the geognostic and physical relations in that locality 

 is very pleasant reading; but, biassed as he was by Werner's 

 theories, Von Buch tried to explain the disturbances of the 

 strata by local collapse, and by the shifting of the centre of 

 gravity in the rocks. The beautiful " Konigsee " near Berchtes- 

 gaden, and the Lake of Hallstadt, were both regarded as 

 local basins of inthrow, and the deep Alpine valleys were 

 attributed to river erosion. The whole massive development 

 of limestone in the higher ranges of the Salzkammergut was 

 taken to be the equivalent in age of the Thuringian " Zech- 

 stein " (Upper Dyas). The occurrence of fossils at Hallstadt 

 and Gosau, and other now famous localities, was repeatedly 

 mentioned by Von Buch, but the fossils themselves were 

 not used in any way to help to determine the age of the 

 rocks. 



In a separate publication Von Buch drew a comparison 

 between the geological succession observed by himself across 

 the Brenner Pass, and that which had been described by De 

 Saussure for the Mount Cenis Pass. Although the idea was 

 good, the rocks and the stratigraphy in these two distant 

 Passes have too little in common to disclose any broad 

 principles of Alpine structure, and the results obtained by Von 

 Buch in this respect were confused and unsatisfactory. 



Some general facts were, however, brought into promi- 

 nence. In this work Von Buch demonstrated the absence of 

 porphyry at Mount Cenis, as well as in the whole Northern 

 Alps, in strong contrast to the enormous development of this 

 rock south of the Brenner Pass; he compared the northern 

 and southern zones of the Alps with one another geologically; 

 showed the relationship of the Jura mountains, to the Alps and 

 he drew attention to the lithological differences in the rocks, 

 and their influence on the scenic features. In later years Von 

 Buch wrote a few short papers on the Hinterrhein district 

 (1809) and on the Bernina Massive (1814). 



One of the most richly endowed of Alpine students was the 

 Ziirich geologist, Hans Conrad Escher (1767-1823). In 1796 

 Escher published a geological survey of the Swiss Alps, and 

 afterwards a series of geological sections from Ziirich to the 

 St. Gothard Pass. He also contributed several smaller 



