300 GEOLOGICAL OBSERVATIONS J.N FRANCE. 



Without cor. 

 for temi)erature. 

 Table of Orgines* 393-000 



heights above The summit of Puy-de-UAmef 751-657 



the level of the ^ r t^ . , , „ . fj^^ot 



gea^ Jt^uy-de^lr'arion, on the edge of the crater GlO'833 



at the bottom of the crater :J: • • • • 574-166 



Puy-de-Barme 561-166 



Orcival 448-000 



Mount Jiughat, on the edge of the crater 574*166 



; at the bottom of the crater 552 500 



Issue of the current of lava from Puy-de-la-Vache 50y 000 



Hake Aidat ........ > .;..... 419-000 



MouiitUins of Croix-Marand 6.93^166 



Village of Mont-d'Or-les-Bains. ................ 523-333 



Cascade of la Dogne,' at bottom 654-000 



— at the top § 694-333 



Rock of the Cousiijs|l , . . . 8P>5-33t>' 



Mountain of Cacadogneil ^)0l'Q6(i 



Summit 



Lava. * Here is found the grand stream of lava from Puy de-Pariou, This 



lava is very fragile, and contains' only sniall crystals of feldtspar, which 

 retain their native hstrt, 



^oii>hyry. -f This mountain is formed of a sort of porphyry, the cement of which, 



not very hard, and of an earthy {^r»y colour,- includes mica and a great 

 many large crystals of feldtspar, which are- cracked and have a vitreous 

 appearance; while those found in the granite, that constitutes the base 

 of these mountains, have a pearly gloss. 



According to Perrier the height of this, mountain above the sea is 700 

 toises j accoRling to Cassini and le Monnier, 757. 



Crater. % 1 '^'^ crater, which is perfectly circular, measures 200 paces round : 



it is covered with graSs, and cattle feed in it. 



Volcanic pro- § ^" ^^^^ cxcur^ion fine feldtspars are found, in large double crystals, 



ductions. in a porphyry, which according to Mr.' von Bueh cannot liave a very dif- 



ferent origin from that of Puy-de-D6me. He adds, that it is a volcanic 

 production, but not lava. ■ . . 



II If we proceed along the ridge of the inQuntain from the top of the 

 cascade of la Dogne, says Mr. von Buch, we arrive at the rock of the 

 Cousins, where we see substances that have much more ai)pearance of 



Basaltes. basaltes, and in which the feldtspar becomes more rare. Continuing 



along the ridge iov*ard Cacadogne, we go round's frightful, semicircular 

 precipice, the sides of which are covered with scoria;. This is the only 



P J) lace in the neighbourhood, that can be termed a crater. From Caca- 



dogne the ascent to the summit of Mont-d'Or is easy. It is an immcHSG 



circus. 



