366 On the Physical Geography of the Alps. 
the general features so far as to cause the crests surrounding the 
basins to appear as naked mountains of snow and ice, while by 
closer examination they are found to be regular rock-ridges. 
These differ considerably in relative elevation; particularly in 
the hindmost, highest parts, it is often so slight, that only some 
grotesque, jagged pinnacles form the boundary of the basin; 
their base is for the most part hidden by the “ firn,” but their 
outline is more or less recognizable by means of the bedding of 
the é‘firn” and the direction of its crevasses. We have also, at 
rather lower altitudes, altogether similar forms not covered by 
snow, which may be compared with them. hey are pretty 
clearly distinguishable from the peculiar “ Kessel-” [cauldron-like] 
valleys, in which the lines of inclination must converge towards 
acentral point. In the Alpine basins [Mulden] there is evidently 
a decided inclination towards the middle in the direction of the 
transverse axis of the two sides; and we can trace more or less 
clearly a kind of central axis downward throughout the whole 
basin. These lines, however, together with the whole basin, 
have a very constant inclination towards its front entrance. In 
very considerable; the largest, among which the firnmeers are 
especially to be remarked, attain to half a square mile [German] 
and more. 
Behind and at the sides they are enclosed by. crests that sur- 
round them in the form of the segment of a circle, subject of 
course to much irregularity. Forwards they pass into narrow, 
extended valleys; the: transition being either gradual, or, aS In 
most cases, rather sudden. ‘his narrow valley or dell [Thalenge] 
Opens into a second open basin, having very often a breadth of 
2000 to 3000 feet [French]. This continual succession of wide 
basins and narrow dells is very conspicuous in all the transverse 
valleys of the Alps, and has already been noticed in the valleys 
of the Aar, Linth, Reuss, Gastein, é&c., by Saussure, L. von Buch, 
Escher, Studer, and others. Similar basins and circus-valleys 
are found in all the Alpine ranges, and in the Pyrenees, the Jura, 
and other mountains, and they have been noticed by Hutton and 
Playfair in England ; their examination, therefore, must have @ 
very general interest. sia 
ransverse Valleys.—Fully to exemplify these phenomena 
the author gives a copious detailed account of the following 
cross-valleys:—1. The Oetzthal, with its seven basins, illustrated 
by a woodcut profile. 'This is described (p. 201) as opening int 
the longitudinal valley of the Inn, five or six miles [German] 
