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Geological Notes on the Valleys of the Rhine and Rhone. By 

 Robert Cu ambers, Esq., F.R.S.E., &c. Communicated 

 by the Author.* 



AUuvial Terraces and Deltas. 



The alluvial terraces in the valleys connected with the 

 Alps, have been referred to by M. Saussure, Mr Playfair, 

 Professor Studer of Berne, and other eminent geologists, but 

 not vs^ith that degree of attention w^hich they seem to merit. 

 Mr Playfair says, — '* The changes that have taken place in 

 the courses of rivers are to be traced, in many instances, by 

 successive platforms of flat alluvial land, rising one above 

 another, and marking the different levels on w^hich the river 

 has run at diff^erent periods of time." He speaks of these 

 terraces as very conspicuous at the Rhine ; one, of w^hich he 

 measured the height, vt^as 122 feet above the present surface 

 of the river. He adds, — " When it is considered that three, 

 or even four, such terraces can often be counted on the banks 

 of this great river, it may fairly be stated, that the evidence 

 of the Rhine having flowed at the height of 380 feet above 

 the present level is very conclusive.'' M. Studer considers 

 these terraces as indicating " alternations of the epochs of 

 repose and activity.'' From the very general neglect of the 

 superficial formations, we are left w^ithout any more definite 

 information on this subject, and no plausible hypothesis has 

 as yet been suggested as to the actual circumstances under 

 which the great detrital deposits of the plain of Switzerland 

 were laid down, and these terraces in the valleys produced. 



In the course of a recent tour in Rhineland and Switzer- 

 land, I was able to make a few observations on the superficial 

 formations in various districts, and also to make some ap- 

 proaches to what I consider a satisfactory conclusion regard- 

 ing the formation of river terraces. In venturing to lay the 

 results before the Society, I trust to meet with that indul- 

 gence which is due to those who advance into a comparatively 

 little investigated field, and whose speculations are aided by 

 little collateral light. 



* Read to the Royal Society of Edinburgh, on the 5th December 1848. 



