GEOLOGICAL OBSERVATIONS IN FRANCE, &C. 275 



\rhere its thickness could be estimated, and extending up 

 the acclivity of the mountain quite to its summit. The pre- 

 ceding winter having been severe, so much snow had fallen, 

 that the heat of summer had not been able to melt it, a cir- 

 cumstance uuheard of before, for the oldest inhabitants 

 could not recollect, that the snow had ever remained longer 

 than the end of June. I conceived this mass of frozen 

 snow might prove the nucleus of a glacier of the second 

 order*: and in fact the following year, when I returned 

 thither in July, I found the snow, far from having dimi- 

 nished, had rather increased, so that the recent production 

 of a glacier on this mountain appeared to me very proba- 

 ble. 



On approaching the summit the stone assumes a fissile 

 character, which it had not below ; and we meet with dode- 

 caedral calcareous spar finely crystallized, and several frag- Spar, 

 ments of gritstone, of which there is a stratum 116 toises Grit. * 

 above the level of the sea. I did not perceive any nodules ^ flj nt# 

 of silex, which are so common on mount Pormonaz. The . 

 loftiest point of Tournette is a very remarkable rock. It Singular rock. 

 is nearly circular, 94 feet high, and 145 in diameter, stand- 

 ing alone on a point of the ridge that forms the summit, 

 and cut perpendicularly nearly alike^on every side. There 

 is no getting to the top of it, but my means of steps cut in 

 the rock on the north-east. It is no doubt from this rock, 

 standing there like a sentry-box, and seen from all the sur- 

 rounding country, that the mountain received its name. 

 The prospect from it is very extensive and interesting. To Prospect from 

 the east it takes in the centre of the grand chain, and all ll * 

 the secondary ones attached to it in succession: to the south- 

 east the mountains Tarenteuse and Maurienne: to the south- 

 west those of the department of the Isere : the chain of 

 Jura to the north-north-west: and the lake of Geneva to 



* Mr. Saussure first distinguished the glaciers into two kinds. The Glaciers of tw* 

 first are included in the bottoms of the high valleys, almost all in a kinds, 

 transverse direction, that terminate at bottom in the low longitudinal 

 valleys, while at top they form grand culs-de-sac surrounded by inacces- 

 sible rocks. Such are those that terminate in the valley of Charnouni. 

 Those of the second kind are not included in valleys, but spread over 

 the slopes of lofty summits. 



T 2 the 



