FORMER GLACIATIOX OF THE ALPS. 357 



former greater extension of the glaciers are displayed with all possible clear- 

 ness and an entire absence of complication. The Adriatic then occupied 

 what are now the fertile plains of Lombardy, extending up to the base of the 

 Alps, as is proved by tlie presence of marine fossils in connection with the 

 morainic debris in that region.* Tbe terminal moraines are marked with 

 the utmost distinctness along the edge of the mountains, where the rivers 

 debouch into the plain, and especially at the southern ends of Lago di 

 Garda and Lago d' Isseo. There seems not to be a single feature of the 

 morainic landscape which is not in harmony with that which we see ice 

 doing at the present time, although on a considerably smaller scale, higher 

 up in the valleys of the same range. 



The same mav be said with almost as much truth alono; the northern 

 flanks of the Alps. The phenomena are, however, much the most decidedly 

 marked in tlie western and northwestern portions of the chain. As we go 

 east we find the evidences of glacial extension less conspicuous, and the 

 proofs of the former presence of water in the valleys more and more striking. 

 All through the Tyrolese and Austrian Alps, especially along the course 

 of the Inn and its tributaries, the rivers once ran with nnich greater vol- 

 ume than they now do, and they have piled up in the vallejs and along 

 the northern flanks of the Alps vast masses of debris, stratified and well 

 water-worn, bearing much more the characteristics of water than of ice 

 action, while striated surfaces and true morainic accumulations are by no 

 means as abundant or as decidedly marked as on the western and southern 

 sides of the Alpine Range. 



The only difficulty in regard to Alpine glacial geology is to separate 

 clearly the results of the action of water, or of water and ice conjointly, from 

 those brought about by ice exclusively, or in other words, to answer the 

 question. What has been effected which is peculiarly the work of ice and 

 Avhich would not have been accomplished if there had been no glaciers? 

 Those who belong to the ranks of the most advanced glacialists cannot see, 

 even in the fine mud deposited in the valley of the Rhine when that river 

 was much larger than it now is, anything but the result of the grinding of 

 tlie glacier along its rockv bed. According to them, the crust of the earth 

 would everywliere have remained uncovered by soil, if ice had not ground it 



* Sep. Desor, Paysage Morainique, Paris et Neuchatel, 1875, pp. 28-4(5: Stoppaiii, L' Era Xeozoica, ossia 

 Descrizione dei Terveni Glaciali s dei loro 'EquiTalenti in Italia, Milano, 1880, pp. 131-192; and Riitimeyer, tJber 

 Pliocen und Ei.speriode auf beiden Seiten dcr Alpen, Ba.sel-Genf-Lyon, 1876. 



