350 M. Brongniart on the Vegetation of 



when I submitted to the Academy the results of an investigation 

 on which it notwithstanding condescended to bestow the most 

 flattering approbation. Since that time, the examination of the 

 fossil vegetables of the different strata of the globe has engaged 

 the attention of the geologists of France, England, Germany 

 and Italy, and remarkable specimens of these fossils have been 

 collected in America, in India, and even in New Holland. The 

 discoveries made in some of these countries have been made 

 known to us by various works ; but the results to which I am 

 desirous of drawing the attention of the Academy for a few mo- 

 ments, are in a great measure founded upon the yet unpublished 

 matters which I have collected on my travels, or which have 

 been transmitted to me by the naturalists of the countries which 

 I have just mentioned, with a liberality for which I cannot too 

 strongly express my gratitude. 



We do not yet, however^ possess sufficient information re- 

 specting the geology and organic remains of the other parts of 

 the world, to be able to form any decided opinions with respect 

 to them. Our results are all based upon the examination of the 

 fossils of Europe and North America, and although from what 

 we already know, it is very probable that they will apply to the 

 other regions, we yet cannot make any positive affirmations on 

 this subject. 



The number of the species of fossil plants known, whether 

 through the works which contain descriptions and figures suffi- 

 ciently accurate to enable us to determine them with some de- 

 gree of certainty, or through the specimens preserved in the 

 collections which I have visited, or in my own private collec- 

 tions amount to 500 or 550.' 



These species are very unequally distributed in the strata of 

 different antiquity, which constitute the crust of our planet; and 

 this inequality in the distribution of the fossil plants, which is al- 

 ready remarkable, when we consider the total number of species 

 contmned in each stratum, becomes still more striking when we 

 compare the numbers belonging to the different classes of each 

 of these floras. 



These latter results necessarily require an exact determina- 

 tion of the species, or genus, or family, or at least of the class to 

 which each fossil plant belongs. We should be transgressing the 



