File:The Quarterly journal of the Geological Society of London (12683091603).jpg

106 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .DcC. 5,
Fig. 2. — The Matterhorriy as seen from the Riffelherg.
E, E, indicate the line of erosion.
9000 feet ; there is a thick covering of snow round it, which con-
ceals the line of erosion and makes it appear to be higher than it
really is.
There is no distinct lower limit to the abraded or rounded portion
of the mountains, but the upper limit of the abrasion is usually well
marked by a change in the outline of the hill-sides from a moderate
to a steeper slope, similar to the indentation produced on a coast by the
waves beating against a cliff*. The nearly uniform height of this
re-entering angle produces a tolerably level line round the mountains,
which I shall speak of as the line of erosion. It is best seen when
the observer is at a distance, or, if near, is only a few hundred feet
helow it, when a horizontal line may often be traced by the eye round
every one of the mountain-tops within its reach ; this is nowhere
more remarkable than in the view from the top of the Splugen Pass.
When standing on the level of the line of erosion, it is often more
difficult for the eye to follow it ; slight inequalities in the ground
which are near at hand concealing or interfering with the view. This
makes it difficult to measure the height of the erosion within 1 00 or
200 feet, even under favourable circumstances. But there are spots
free from this difficulty : whoever has ascended from Zermatt to the
Kiffelberg must remember the distinctness with which the conical
Riffelhorn rises from the flat at the top of the rounded Riffelherg :
the line of erosion is there as well marked as at the foot of a sea-
cliff, being (by my aneroid) between 9000 and 9100 feet above
the sea.
When the observer is more than 1000 feet below the line, it will
require a practised eye to estimate its height within 500 feet ; and
the result will be merely a rough guess, which will usually prove to
be below the truth. In the following statements I have pointed out
those measurements which are most to be relied on ; but in general,

• Some excellent profiles of cliffs and beaches have been given by Mr. Godwin-