PREFACE. 
9 
Volumes and Memoirs on Swiss Geology and 
Physical Geography. Jaccard in his work on the 
Jura and Central Switzerland enumerates no less 
than 959, but among the most important I may men- 
tion Heim’s magnificent work, Mechanismus der Ge- 
birgsbildung, Studer’s Geologie der Schweiz, Agassiz’s 
Etudes snr les Glaciers, Suess’s Das An flit z der Erde, 
Favre’s Recherches Geologiques ; for the fossils that of 
Heer; and among shorter publications, in addition to 
those by the geologists already referred to, particularly 
those of Bonney, Morlot, Penck, Ramsay, Rtitimeyer, 
and Tyndall. 
I have dwelt specially on the valleys of the Arve, 
Rhone and Rhine, the Reuss, Aar, Limmat and 
Ticino as types of longitudinal and transverse valleys; 
and because they are among the districts most 
frequently visited. They have, moreover, been ad- 
mirably described, especially by Favre, Heim, Rene- 
vier and Rtitimeyer. 
I am fully conscious of the imperfections of this 
book: no doubt by waiting longer it might have been 
