76 M. Ch. Martins on the 



on the sides of the valley of Sallenches, were deposited in 

 the bottom, and we now find them lying around the gorge 

 occupied by the baths of St Gervaise. We can even notice 

 before the bath-house itself inclined beds of rolled pebbles, 

 mingled with angular blocks, certain proofs of tlie ancient 

 existence of a small glacial lake like that of Tacul, which is 

 found in the angle formed by the junction of the glaciers of 

 Geant and Lechaud, the principal affluents of the Mer de 

 Glace of Chamonix. 



At the distance of a few kilometres, the erratic blocks de- 

 posited by the glacier of Eonnaut are replaced by those of 

 the lateral moraine of the glacier of the Arve, which reap- 

 pears on the sides of the mountain, and prevails without in- 

 terruption from the village of Combloux to the small town of 

 Sallenches. It is to the learned Bishop of Annecy, M. Ren- 

 du, that we owe the discovery of this moraine. He had re- 

 marked with surprise, that the continuity of the cultivated 

 fields, which, from the bottom of the valley, rise to a great 

 height, was interrupted by a zone of forests. Entering within 

 tlie shade of these dark pines, he immediately perceived the 

 cause of this singularity. In this zone, the ground disap- 

 peared under an accumulation of erratic blocks, piled one 

 above another, and rising to the height of the trees. Every- 

 where masses of protogine were seen, measuring from 10 to 

 20 metres in every direction. The ridges of these masses 

 were as sharp, and the angles as acute, as in the moment 

 when they were detached from the peaks of Mont Blanc. 

 Not only have the trees shot forth between the blocks, but 

 they have taken possession of the blocks themselves, and 

 often a beautiful tuft of pines and birch vegetates, like a sus- 

 pended forest on a foundation of granite. The traveller has 

 as much difficulty in forcing a passage through this labyrinth, 

 as if he had gone astray among the moraines of the Mer de 

 Glace at Chamonix. Wherever the rivulets have cut up the 

 ground, he notices this mixture of sand, pebbles, and angular 

 blocks heaped confusedly, which characterizes the deposits 

 made by glaciers. It is only at the depth of several metres 

 that he finds the schistose strata of the mountain. The most 

 gigantic blocks of the moraine of Combloux are found at the 



