BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 15, pp. 369-378 August 13, 1904 



POST-GLACIAL CHANGES OF ATTITUDE IN THE ITALIAN 



AND SWISS LAKES 



BY FRANK BURSLEY TAYLOR 



(Presented before the Society January 1, 1904) 

 CONTENTS 



Page 



Introduction 369 



The structure of torrent deltas 370 



Lake Maggiore 371 



Lake Como. 375 



Lake Garda 376 



Lake Lugano 376 



Lake Geneva 377 



Lake Lucerne 377 



Conclusions 378 



Introduction 



During a trip abroad in the summer of 1894 the writer spent about 

 two weeks studying the lakes of northern Italy in search of evidences of 

 change in the relative attitude of the lakes and the land. In the autumn 

 part of another week was spent in similar studies on lake Geneva and 

 two days on lake Lucerne. The results attained seem to have some 

 interest not only in their local bearings, but also in their general rela- 

 tions to the Alps. This paper, however, is necessarily of a preliminary 

 nature, for two weeks was much too short a time for an exhaustive study 

 of the four Italian lakes examined. 



It was found that all three of the larger lakes of northern Italy — 

 Maggiore, Como, and Garda — formerly stood in different attitudes toward 

 the land from those in which they now stand. Their surfaces were rela- 

 tively higher at the north and sloped to the south about 1 foot to the 

 mile, as compared with their present surfaces. 



It might be thought that the abandoned shorelines of lakes of such 

 magnitude — 30 to 37 miles long, and with average widths of from 2 to 5 

 miles — would show wave-made beaches, but, excepting the southern ex- 

 panded part of lake Garda, which reaches a width of 10 miles, no certain 

 evidence of wave work was found above the present shorelines. The 

 main evidences of the former attitudes of the lake surfaces are the old 



L— Bull. Geol. Soc. Am., Vol. 15, 1903 (369) 



