TERRACES IN SWITZERLAND. 39 



country is undulating, seeming like the bottom and shores of an ancient sea. But 

 the river terraces are few and imperfect. Near Heidelberg, on the north bank, a 

 few are placed along the foot of the hills. At Wiesbaden and Frankfort, the 

 detrital matter appeared to me like old sea-bottoms, and the long sandy plain passed 

 over between Frankfort and Heidelberg, is probably a terrace of similar origin. 



For the next 200 miles, between Heidelberg and Basle, I can only say that the 

 valley of the Rhine is broad most of the way, and I saw but a few well-marked 

 terraces, with now and then a beach above them. But I doubt not that examina- 

 tion would show them both to be numerous, though probably not so distinct as in 

 narrow valleys. Upon the whole, I may say that the phenomena of surface 

 geology on the Rhine, as far as I observed them, correspond entirely with those 

 upon the larger rivers of our country. 



Switzerland. 



We next reached Switzerland, but in passing towards Zurich, through Bruges 

 and Baden, we continued for a time along the south bank of the Rhine. A little 

 beyond Basle, near the mouth of the Birs, terraces are very fine; and, in fact, 

 they continue to be exhibited along the Rhine as far as I followed it, viz., to 

 Mumpy. The two lowest are very distinct, and then we frequently have irregular 

 ones still higher, which I should call beaches. Near Basle, I measured a terrace, 

 the third in height — and, so far as I saw, the highest — which I found, by the 

 aneroid barometer, to be 228 feet above the Rhine, and 983 feet above the ocean. 

 At Rhinefelder, I took the approximate heights of three successive terraces, and 

 observed at least one other below the lowest of these, and also what seemed to 

 me to be beaches above the highest; these are represented on section No. 41. The 

 highest, it will be seen, is 306 feet above the Rhine, and 1226 above the ocean. 

 Further up the Rhine, near Mumpy, I measured what seemed to me a beach, 696 

 above the river; and found the highest part of the road between Mumpy and 

 Bruges to be 941 feet above the Rhine at the former place, and 1915 feet above 

 the ocean. At this summit, the detritus was perhaps drift, though I thought it 

 had been modified by water subsequently. After leaving the Rhine at Mumpy, 

 we followed up a small stream with terraces, but they slope rapidly towards the 

 stream, and are, properly speaking, glacis terraces. 



Around Bruges, where the Reuse and Limmat join the Aar, the terraces are 

 very fine, and may be seen extending down the river several miles. Between 

 Bruges and Zurich, through Baden, we see some terraces on the small streams, but 

 they are not striking. Most of the detritus seemed to be drift, yet somewhat 

 modified. 



The northern part of Lake Zurich I found to be fringed by three or four terraces, 

 which are often chosen as the sites of villages and scattered houses. Leaving the 

 lake at Horgen, on the west shore, we ascended the ridge separating Lake Zurich 

 from Lake Zug. Section No. 42 will give some idea of the terraces on that route. 

 Two of the terraces I measured; and the beach represented as 843 feet above the 



