342 Proceedings of the 



memoir also contains allusions to various other points, which are to 

 be treated in M. Barbe's forthcoming work ; but they are not 

 developed with sufficient minuteness or clearness to admit of their 

 being examined. The reporter, however, considered that M. Barbe 

 deserved the approbation of the Academy, as an encouragement to 

 continue his researches on a subject highly important to science. 



Fossil Plants. On the 18th of July, M. Beudant made a report 

 to the Academy, on the publications and manuscript memoirs of M. 

 Adolphe Brogniart, on this subject. M. Brogniart has already pub- 

 lished five numbers of his work, containing thirty-one sheets of letter- 

 press and seventy lithographic plates, representing a great number of 

 fossil plants, compared with the analogous living plants, placed in 

 juxtaposition with them. In studying fossil plants, a very different 

 system from that in which a knowledge of living plants is obtained, 

 must necessarily be pursued. The organs of fructification, which, in 

 botany, supply the characteristics of the primary class, are almost 

 invariably deficient in fossil plants ; and the leaves and stems, which 

 in living plants are usually the object of a very superficial study, are 

 all that remain. M. Brogniart has, therefore, especially applied 

 himself to examine minutely the organization of these parts, with a 

 view of appreciating with exactness the relation of the characteristics 

 to be drawn from them, with those derived from the organs which 

 usually serve as grounds for classification. He has carefully exa- 

 mined the nerves of the leaves, and the different mode of insertion of 

 these organs in each family ; he has investigated the modifications 

 which the different parts of the internal structure of plants can pro- 

 duce on their exterior, and has, in a word, applied himself to the 

 most minute researches on every characteristic of living plants, which 

 could by any possibility be preserved in those buried in the bosom of 

 the earth. He has also endeavoured to ascertain the different mpdifi- 

 cations, which compression and the various modes and degrees of 

 decomposition might produce in fossil plants ; and has distinguished 

 with the greatest precision the cases in which the family, the genus, 

 and even the species of a plant, may be pronounced on with cer- 

 tainty, from those in which doubts may be entertained on some of 

 these points, and it may, therefore, be only safe to decide on the 

 genus, the family, or the class of a plant. By these means M. 

 Brogniart has succeeded in distinguishing among fossil plants, spe- 

 cies, genera and families, perfectly analogous to those of living 

 plants ; and has already disposed more than five hundred species 

 of these plants in their natural order, and, by comparing them with 

 living plants, enabled us to appreciate the immense distinctions ex- 

 isting between the ancient and modern botanical world. M. Brog- 

 niart has not stopped here, but has proceeded to examine the laws 

 regulating the distribution of fossil plants in the different beds of the 

 earth, and compared these with the laws of the geographical distribu- 

 tion of plants on the surface. He has ascertained with certainty, 



