382 NODULES OF LAVA IN CLINKSTONE. 



multitude of little needles of amphibole, or pyroxene; sq 

 that they might be taken for fragments of a hornblende 

 rock, if some of them did not exhibit unequivocal marks of 

 the action of fire, 

 fndkind. B. A porous, tumefied lava, of a gray and blackish gray 



ground, with needles of pyroxene, and laminse of feldspar. 

 This is the most common variety. 

 Kot peculiar to 3. This fact is not peculiar to the rock Sanadoire and 

 this rock, those iu its vicinity: a large bowklered block in the torrent 



of Prent-Garde, coming from the lake of Gueri, exhibited 

 to us the same phenomenon. The klingstein is a variety of 

 that of Sanadoire, of a blueish gray colour, and less po- 

 ly edral in its fracture. 

 3d kind. & The lava it contains is gray, and composed of very 



small crystals mingled together. 

 Found in an- 4 - ^ e c ou]d not visit la Vddrine, another phonolitic 

 other moun- mountain on the cast of Mont-d'Or, but Mr. Menard 

 informs us, that he found there the same peculiarities as at 

 Sanadoire, which had wholly escape^ his notice at his first 

 visit to that mountain, 

 and probably in It is not in the simple clinkstone, that we found these 

 several places. nodules f Java; perhaps they would equally be found in 

 the porphyry with base of clinkstone of the environs of lake 

 Gueri, Puy Gros, the rock of Dardanche, &c. By an at- 

 tentive research, employing the time requisite for an exami- 

 nation of this interesting part of the Monts-d'Or, we have 

 no doubt they would be found in much greater number. 

 One single specimen has presented us with two or three 

 Size of the nodules. Their size varies from a few cubic millimetres to 

 nodules. fifteen cubic centimetres [from one or two cubic lines to 



near a cubic inch ] 

 This stone ^is stone has always been considered as a lava in 



therefore a France, either under the name of greenish petrosiliceous 

 lava, or of prismatic and tabular greenish basaltes : but its 

 being found among volcanic substances was the sole ground 

 of this opinion, for marks of the action of fire had no 

 where been observed on it. The volcanic origin therefore 

 of the rock Sanadoire, long disputed, is now evidently 

 proved by the presence of the nodules of lava it contains, 

 which presupposes the rock to hare been in a state of 

 fluidify. 



IX. 



