1848.] BUNBURY ON FOSSIL PLANTS. 131 



containing belemnites really belonged to the same geological epoch, 

 and he refers the whole group, without hesitation, to the age of the 

 lias. This paper was followed by one from M. Adolphe Brongniart, 

 stating the result of his examination of the fossil plants from this 

 anomalous deposit. He enumerates nineteen species, besides some 

 others which were not in a state to admit of determination ; and of 

 these nineteen he pronounces seventeen to be positively identical with 

 species of the coal formation, the remaining two being peculiar and 

 previously undescribed. In a subsequent communication, published 

 in the fifteenth volume of the * Annales,' M. Elie de Beaumont de- 

 scribed a series of strata of vast thickness occurring in the Alps be- 

 tween Brian9on and St. Jean de Maurienne, and which he considered 

 as belonging to the same system with those previously described in 

 the Tarentaise. In the upper part of this series, at the Col de Char- 

 doniiet, not far from Brian^on, he collected several additional speci- 

 mens of fossil plants, which were likewise ascertained by M. Adolphe 

 Brongniart to be identical with well-known species from the true coal 

 formation. M. de Beaumont arrived at the conclusion that this great 

 system of beds, containing (according to his observations) fossil plants 

 of carboniferous species both in its upper and lower members, and 

 containing also belemnites and even ammonites, was the representa- 

 tive not only of the lias, but of the whole or greater part of the Ju- 

 rassic series. Thus the fossil plants {Calamites, Sigillarice and 

 Lepidodendra)oii\\Q Col de Chardonnet, which are absolutely identical 

 with those of the coal-measures, belong to strata which (according to 

 this view) are equivalent to the middle or upper parts of the oolite. 



I am not aware that any further observations were made upon this 

 singular anomaly until the year 1844, when the Geological Society of 

 France held their meeting at Chambery, and their attention was natu- 

 rally directed to so remarkable a fact. A great number of the members 

 then visited the localities in the Tarentaise which had been described 

 by M. Elie de Beaumont, and the observations which they made are 

 recorded in the Bulletin of that Society, to which I must refer for 

 ample details of the geological structure of that part of the Alps. 

 They confirmed the pre^dous observations of M. de Beaumont, and 

 arrived (I believe unanimously) at the conclusion that the strata con- 

 taining ferns really alternated with those containing belemnites, and 

 could not be considered otherwise than as parts of the same formation. 



In 1846 Mr. Horner, then President of our Society, called the 

 attention of English geologists to this subject in his Anniversary 

 Address, and he proposed an explanation of the anomaly, on which I 

 shall afterwards have occasion to make some remarks. 



When I was in Italy, during the past summer, it was suggested to 

 me by some of my friends that I should examine the fossil plants 

 from the Tarentaise, of which a considerable collection exists in the 

 museum at Turin. Twenty years had elapsed since the publication 

 of M. Adolphe Brongniart' s memoir, and it was thought that the 

 additional materials which had been collected might possibly tend to 

 throw some new light on the question. Accordingly, during my stay 

 at Turin, I devoted some days to a careful examination of the speci- 



