On the Physical Geography of the Alps. 365 
stands how the great valleys excavated by rivers continually 
eroding strata more or less soft and destructible are distinguishable 
from the ramifying valleys of elevated districts, which are some- 
times widened out into basins and sometimes struggle through 
narrow ravines. In the latter, mountain masses of ever varying 
profile rise on both sides many thousand feet high, whilst in the 
former case, above the slopes on either side, we meet with nearly 
horizontal plateaux, but slightly raised above the valleys. 
he Alps, on account of the vast mass of the mountains and 
the various inclinations and summits, it becomes very difficult to 
distinguish definite “groups” and their laws. Vegetation, also, 
and culture, and especially the products of weathering, obscure 
the original form of the district.. To correct the errors arising 
tom hence it is highly desirable to examine these valleys at in- 
tervals more or less extended, as we were enabled to do in the 
_ Tavern Alps and in the Oetz Valley. 
The following researches have especial reference to the crys- 
talline slates of the Upper Alps; we did not, however, omit to 
study the characteristic phenomena of the limestone Alps. And 
in this we have sought, by our determinations of height, by the 
comparison of inclinations, and by the execution of numerous 
profiles, to preserve assured data which may serve to give accu- 
rate and well-defined ideas of the characteristic forms. Such 
Special researches are not without value for the general questions 
of geology. L. von Buch, in his well-known “ Researe es on 
Granite and Gneiss,”’ has shown how intimately their external 
orms are connected with the most important processes that have 
e. 
asin-shaped. Valleys in the Alps.—tna considering the char- 
acteristic forms of the Alpine valleys, much importance is to be 
attached to their upper extremities. Here are found peculiar ba- 
sin-like cavities, which are sometimes occupied by the great Firn- 
meers, so essential to the existence of glaciers. Such a cavity is 
up of slight inequalities, are well qualified to exhibit more clearly 
character of these circular cavities ; and only interfere with 
% Compare Voigt on the Formation of Valleys, 1791. 
t ne ae de Géognusie, i, 1819. 
¢ Abhand. d. Acad. Berlin far 1842. 
Srcoxp Series, Vol. XIV, No. 42.—Nov., 1852. 47 
