David Milne-Home on Ancient Glaciers. 51 
side. On opposite or north side of the veins, not only was 
furrow not continued, but the general surface of the schist 
rock not so low—having been protected, as it were, by the 
quartz veins. 
It seemed very plain that these appearances indicated the 
passage and pressure of ice, and ice of an enormous weight 
and mass to produce such general smoothing, and also such 
extensive groovings or furrows; whilst the interruption of 
these by the quartz veins showed unequivocally that the 
glacier moved northwards down the valley. 
The height of this spot, judging roughly by sympiesometer, 
was 1300 feet above Chamouni, and therefore 4725 feet 
above the sea. 
On this, the west side of valley, there is an elongated hill, 
running north and south about 1500 feet higher—the general 
direction of which is parallel to the furrows and scratches. 
It occurred to me, that reason why these deep furrows 
formed in this locality, and not in any of the other places be- 
fore mentioned, where rocks found but slightly scratched, was 
that bere the whole weight of glacier was pressing on the 
rocks; whereas at the hill of Chavant, on opposite side of 
valley, the weight of glacier on the rocks not so great, in 
consequence of the slope upwards. When under the Mer de 
Glace, I observed that the glacier was not one solid mass of 
ice, but that it consisted of great blocks, very irregular in 
size and shape; and therefore the glacier would not press on 
- the rocks with equal force at all points. Hence furrows 
would be formed in different places. 
Observed here several of the natural cavities or depressions, 
to which Balmat had referred, with the inner surfaces quite 
rough, as if not abraded or touched by the glacier. 
7. In this part of valley of Chamouni, erratic blocks of 
prodigious size abound. On hill of Chavant they reach to 
top, and in some places rest on smoothed rocks. This is case 
also on rocky terrace just described on west side of valley. I 
account for their position by supposing that as the glacier 
shrunk back over its bed to its present limited dimensions, it 
left these blocks where we now find them on the smoothed rocks. 
Of course, when glacier was passing over and smoothing 
