
314 STRUCTURAL AND FIELD GEOLOGY 
denudation, and in many places also where probably no 
boulder-clay was ever deposited. The observer should take 
particular note of the configuration of the hills and mountains 
of a glaciated region (see Plate LIL). land (yhijeneiae 
been subjected to extreme glaciation generally shows flowing 
contours. Projecting prominences and crags are smoothed 
and rounded off on the side that faced the ice-flow; while the 
opposite side, protected by its position, may retain its 
original roughness. The smoothed face is termed the Séoss- 
sette, and the non-glaciated face, the Lee-sezte. Whole 
mountain-slopes may exhibit a rudely mammilated surface, 
the rounded rock-surfaces being often striated. Sometimes 
the ice-markings are fresh and readily recognisable; at other 
times they have almost vanished—the mere “ghosts of 
scratches.” Even when they have disappeared, however, the 
mammilated outlines of the rock-masses are cogent evidence 
of the former presence of glacier-ice. These rounded hum- 
mocks or vroches moutonnées, as they are called, generally 
indicate clearly enough the direction of ice-flow. In the case 
of abrupt crags and tors the stoss-seite is usually steep, while 
the lee-seite assumes the form of a long sloping ridge. This 
phenomenon is known as crag-and-tatl. Sometimes the tail 
is composed entirely of glacial.detritus (boulder-clay, gravel, 
etc.). More frequently (especially when the crag is very 
prominent and of considerable dimensions) the “tail” 
consists largely of solid rock, usually covered with a less or 
greater thickness of boulder-clay, ete. 
Terminal Moraines: Perched Blocks, etc—In many of 
our mountain valleys, angular blocks and earthy débris are 
sprinkled more or less abundantly over the ground, up to 
very considerable elevations. In the bottoms of the valleys, 
knobby ridges, mounds, and hillocks, composed of the same 
materials, are of common occurrence. The character of the 
deposits, the peculiar shape of the hillocks, etc., and their 
position, are comparable in all respects to similar phenomena 
occurring in the glacier-valleys of alpine regions, There can 
be no doubt that they are the zermznal moraines of extinct 
glaciers. Low ridges or banks, or lines of morainic debris 
running along the mountain-slopes of many highland valleys, 
correspond to the dateral moraines of existing glaciers, Perched 

