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M, Adolphe Bronyniart and M. Goeppert on the Distribution 

 of Fossil Plants in the different Geological Formations. 



1. On the great divisions of the Fegetable Kingdom occur- 

 ring in the different Geological Formations. By M. 

 Adolphe Brongniart. — 2. General Summary of the 

 Families and Species of Fossil Plants occurring in the 

 different Formations. By M. GOEPPERT. 



1. On the great divisions of the Vegetable Kingdom occurring in 

 the different Geological Formations. By M. Adolphe Brong- 



NIART. 



The difficulties presented by the determination of the re- 

 lation of fossil plants to living ones, have been long known. 

 The isolation of the different portions of an individual plant, 

 and, in most cases, their very imperfect preservation, owing 

 to which the naturalist is often obliged to content himself 

 with the examination of the least important characters, are 

 the principal obstacles which meet us in this study. 



The more the plants whose remains are submitted to our 

 investigation are removed by their organization from those 

 which form the usual object of the examination of the bota- 

 nist, the more do the analogies become difficult to ascertain. 

 The more we ascend in the succession of time towards the 

 first geological epochs, and the more we become removed 

 from the present creation, the more do the differences in- 

 crease in amount between the living and the fossil beings. 

 This general law has been well ascertained in regard to the 

 animal kingdom, and it is not less true as respects the vege- 

 table. 



Thus, the greater number of the fossil plants of the ter- 

 tiary formations belong to genera at present existing, and 

 only exhibit specific differences ; such are the pines, elms, 

 birches, maples, nympheae, &c. 



The fossil plants of the secondary formations can be al- 

 most always referred without hesitation to known families, 

 but they seem in most cases to constitute new genera. 



In the more ancient strata, and more particularly in the 



