210 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



recently made at Petit-Coeur, a village in the Tarentaise, east of 

 Chambery ; where he had seen resting on talcose gneiss and horn- 

 blende schist, a series of sedimentary beds, which prevail over a 

 great extent of that country, the lowest of which, a micaceous sand- 

 stone alternating with a black slaty rock, is surmounted by a bed of 

 fissile argillaceous limestone containing Belemnites, and this last 

 passes insensibly into a black slaty clay containing impressions of 

 plants identical in species with some of those belonging to the true 

 coal formation. M. de Beaumont concludes his detailed description 

 in these words : — " II me parait done incontestable que le systeme de 

 couches qui, a Petit-Coeur, contient les Belemnites et les impres- 

 sions vegetales, et qui s'enfonce sous toutes les autres couches non- 

 primitives de cette partie des Alpes, appartient a la formation du 

 lias." The plants were carefully examined by M. Adolphe Bron- 

 gniart, and in an accompanying memoir descriptive of them he states, 

 " que I'identite la plus parfaite existe entre ces plantes et celles 

 du terrain houiller, tandis qu'il n'y a aucun rapport entre elles et 

 celles qui se trouvent habituellement dans le lias, ou dans les ter- 

 rains oolitiques." He enumerates among others of Petit-Coeur, 

 Neuropteris tejiuifolia, found at Liege and Newcastle; and Pecopteris 

 polymorpha, one of the most common in the coal-fields of France. 



At the meeting of the Geological Society of France at Chambery 

 in autumn IS^'i, an account of v/hich we have received since our 

 last Anniversary*, the attention of the members was directed to 

 this most remarkable fact, in a memoir by M. Rozet ; and after- 

 wards, several vv'ho attended the meeting visited Petit-Coeur. The 

 observations of M. Elie de Beaumont and M. Adolphe Brongniart 

 were confirmed in every particular ; they found abundance of the 

 vegetable remains, and of Belemnites below them. The report 

 farther states : — " 11 a ete evident aussi, pour tous les membres de 

 la Societe, que Ton ne pent aucunement admettre I'explication d'un 

 plissement qui aurait rapproche les fossiles de deux formations et 

 produit une alternance apparente entre les couches a Belemnites et 

 les couches a empreintes. Ce sont les memes schistes et la meme 

 formation qui renferment ces deux genres de fossiles que Ton avait 

 cru pendant longtemps appartenir a des epoques geologiques tres 

 eloignees Tune de I'autre." M. Sismonda, who was present, stated, 

 that in another locality he had found Ammonites in a prolongation 

 of the same bed ; and in reply to M. Agassiz, also present, affirmed, 

 that he had found this bed containing Belemnites and coal-plants 

 over an extent of from twenty-five to thirty leagues. We have thus 

 the same species of plants continuing to exist throughout the whole 

 Carboniferous, Permian and Triassic periods, and into that of the 

 lower portion of the oolite age. I need not say how important a 

 bearing this remarkable fact has on the theories of climate, and of 

 the prevalence of an atmosphere loaded with carbonic acid gas 

 during the Carboniferous period. 



M. Adolphe Brongniart, in his memoir above cited, thus accounts 



* Bulletin de la Soc. Geol. de France, vol. i. new ser. p. 601. 



