Sculpturing of the Mountains. 301 
valley, often at the distance of several miles, he 
beholds another line rising up to the same height with 
that on which he stands, and formed of the same 
horizontal strata of pale sandstone. The bottoms of 
these valleys are moderately level, and the fall of the 
rivers flowing in them, according to Sir T. Mitchell, is 
gentle. The main valleys often send into the platform 
great bay-like arms, which expand at their upper 
ends ; and on the other hand, the platform often sends 
promontories into the valley, and even leaves in them 
great, almost insulated, masses. So continuous are the 
bounding lines of the cliff, that to descend into some 
of these valleys, it is necessary to go round twenty 
miles. The first impression from seeing the corre- 
spondence of the horizontal strata, on each side of 
these valleys and great amphitheatre-like depressions, 
is that they have been in chief part hollowed out, like 
other valleys, by aqueous erosion; but when one 
reflects on the enormous amount of stone which on 
this view must have been removed, in most of the 
above cases through mere gorges or chasms, one 
is led to ask whether these spaces may not have 
subsided .” 1 
It will be noted that Darwin suggests that the 
valleys have been formed by subsidence or a sinking 
of the strata — a view that is not supported by more 
recent observers. 
Govett’s Leap is a “ tremendous rent or depression 
1 Darwin : “ Geological Observations,” 2nd edition, p. 151. Lond., 1876. 
