ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixvii 



M. Scipion Gras"^ read a long communication on the geological 

 constitution of these beds, and the differences which distinguish 

 them from the Jurassic formation. In the course of this memoir, 

 M. Gras gives his reasons for placing these anthraxiferous beds 

 amongst the transition or palaeozoic rocks. He quotes the Yerrucano 

 of Tuscany, which they greatly resemble, to support his views, and on 

 the strength of the resemblance between them, as observed by many 

 geologists, and from the fact of true carboniferous fossils having 

 been found in the Verrucano, he places the anthraxiferous beds of 

 the Alps in the same carboniferous horizon. 



Some correspondence on this subject subsequently took place be- 

 tween M. Sismonda and M. Elie de Beaumont, w^ith especial refer- 

 ences to the age of the Verrucano at Jano in Tuscany. The ques- 

 tion of the age of these anthraxiferous beds of the Alps is one which 

 has occupied the attention of every geologist who has visited the 

 country, and a long list of writers and of memoirs is given in the 

 Bulletin, all having reference to this much-discussed question. The 

 last communication on the subject is from M. A. Sismonda, who, 

 in a letter addressed to M. Elie de Beaumont, gives an account of 

 the fossils from the Col des Encombres (Savoy) and the Col de la 

 Madgelaine in the valley of the Stura (Piedmont). They occur on the 

 route leading from Saint Michel-en-Maurienne to the Tarentaise, and 

 confirm the opinion of M. Elie de Beaumont, that the anthraxife- 

 rous formation of the Central Alps cannot be referred to a more 

 remote period than that of the Lias. The fossils occur principally 

 at the junction of the dark schistose crystalline limestone with the 

 calcareous beds called Calcaire de Villette. The writer concludes 

 that the anthraxiferous beds of the Alps are newer than those of 

 Jano in Tuscany, the latter being below the Verrucano, which he 

 identifies with the infra-liassic conglomerate of Valorsine and Ugine, 

 whereas in the Alps the anthraxiferous beds are above the con- 

 glomerate. Moreover, the Jano fossils are decidedly palaeozoic. 

 The only resemblance between the two formations consists in their 

 flora. But geologists now know that the flora of a formation is not 

 so sure an identification of age as the fauna. It would be an inter- 

 esting investigation to inquire into the cause of this difference. 

 Possibly vegetable life was not so easily destroyed by the changes 

 in the conditions of life and by the convulsions of the ancient world, 

 as the more delicately organized individuals of animal life, and the 

 flora of one period was thus more frequently preserved and carried 

 on into succeeding epochs. 



Now it is generally admitted, that the anthraxiferous beds contain- 

 ing vegetable impressions, supposed to indicate carboniferous species, 

 alternate with Jurassic beds containing Belemnites, &c. ; and some 

 geologists have endeavoured to explain this anomaly by local inver- 

 sion or contortion ; the most recent investigations, however, would 

 seem to controvert this view, for the beds are perfectly parallel, 

 and there appears to have been no contortion or folding over of 



* Vol. xii. p. 255. 



