368 On the Physical Geography of the Alps. 
the fall is here always more cousiderable. A fine example of this 
occurs in the valley of the Inn, the unusually broad plateau of 
which, at the Maloja Pass, descends towards the south with steep 
precipices. 
Longitudinal valleys of the second division commence as soon 
as they descend to a certain height and pass as broad depressions 
between parallel mountain-chains, which very often belong to 
different geological formations. The fall then becomes trifling ; 
the valley-bottoms are filled with beds of gravel; they are always 
broad, and often of great longitudinal extent, and are almost 
cations, and have attained historic celebrity ; in these cases t 
longitudinal valleys form the most important roads through the 
A uch narrow passes are frequently found when the valleys 
leave the Alpine districts and descend towards the northern oF 
southern plains, as in the case of the Porta Westphalica. In 
comparing the longitudinal and the transverse valleys, we fi 
portant, and to be very various in different districts. In a district 
where plateaux predominate, and which is intersected only by @ 
few valleys, these lateral valleys are but few and of a trifling ex~ 
tent. In the Alps, however, they are very numerous and have 
manifold peculiarities. A description of these, and of the Valleys 
of the Limestone Alps, succeeds. etre 
Forms of the Mountain-chains (p. 215).—T he division of the 
Alps into the “groups” [massifs], previously referred to, appears 
to be far more regular, both in an orographical and a geogn : 
their combinations, He finds, particularly in the larger “ groups” 
crystalline slates of the Central Alps, that two chief 1n- 
