134 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 29, 



It will be seen that after the most careful examination which I 

 have been able to make of the fossil plants in question, I have come 

 to the same conclusions as M. Adolphe Brongniart with respect to 

 their general agreement with those of the coal-measures ; though I 

 have not been able to distinguish so great a number of species as he 

 did, nor to speak with the same confidence respecting the greater 

 part of them. So remarkable a fact as the association of plants cha- 

 racteristic of one formation with animal remains supposed to charac- 

 terize another and much later one, seems well-deserving of the atten- 

 tion of geologists. The twenty years which have elapsed since this 

 fact was first observed, — twenty years rich in geological research and 

 discovery, — have brought to light no parallel case ; nothing has been 

 discovered tending to soften or explain the anomaly ; the association 

 of coal-plants with belemnites at Petit Coeur still stands an isolated 

 and exceptional phsenomenon. 



Some, perhaps, may be disposed to object that our materials are not 

 sufficient to establish the fact of the identity of these plants with 

 those of the coal-measures. It is quite true that the greater part of 

 them are in an unsatisfactory condition ; and it is also true that in 

 many instances plants of very distinct species, and even belonging to 

 distinct genera, caimot be distinguished unless by an examination of 

 specimens in a perfect state. But two or three of the fossil plants 

 contained in this Alpine formation are so distinctly characterized, 

 that there seems no reason to doubt their identity. And this at least 

 may be affirmed with confidence, — that many of them are undistin- 

 guishable from plants found in the true coal-measures, while none 

 have any close resemblance to those of the lias or the oolites. 



The fact, that the strata which yield these plants do really alter- 

 nate with those containing belemnites, seems to be established by 

 such strong testimony that it is difficult to dispute it. We have not 

 only the evidence .of M. de Beaumont on this point, but that also of 

 Professor Sismonda and of the Abbe Chamousset, both of whom are 

 intimately acquainted with the district in which these fossils occur, and 

 have had great experience in the investigation of Alpine geology ; 

 and both assured me, that no one who examined the localities could 

 doubt that the beds containing these different kinds of fossils were 

 really members of the same geological formation. But it was sug- 

 gested by M. IMichelin, at the meeting of the French Geological So- 

 ciety at Chambery, that the belemnites (which I believe are undeter- 

 minable as to species) might not be of the importance that had been 

 supposed, in reference to the age of these rocks. He was inclined to 

 consider it an instance of the occurrence of the belemnite form in the 

 carboniferous period, rather than of the continuance of the same spe- 

 cies of plants through several successive epochs. It is true that am- 

 monites also have been found in certain strata of the same district, 

 and which both M. de Beaumont and M. Sismonda consider as form- 

 ing part of the same series with those in question ; but this latter 

 conclusion is, I believe, not admitted by the Abbe Chamousset. If 

 the determination of the age of these strata rests on the belemnites 

 alone, it may, I think, well be considered doubtful. 



