M. De Candolle on Fossil Vegetables. 83 



position, which points out, at the same time, the epoch of their 

 existence, and their habitat on the ancient surface of the globe. 

 In the latter part, he examines the fossils found in every forma- 

 tion of stratified deposits, in a variety of places ; he gives the 

 proportions of the great classes of vegetables which are contained 

 in each of these formations, and finishes by drawing curious 

 conclusions concerning the condition of the earth's surface at the 

 epochs, indicated by the relative position of the formations. 



The Prodromus of Mr Brongniart has become the ground- 

 work of all the more recent investigations concerning fossil vege- 

 tables. Since 1818 he has himself published additional descrip- 

 tions.* In England, Messrs Lindley and Hutton, who combine 

 all the requisite botanical and geological knowledge, have con- 

 junctly undertaken a fossil flora of Great Britain, comprising 

 figures of vegetables found in a fossil state in that country .-f- 

 Though usually adopting the views of Mr Brongniart, they still 

 sometimes differ from him, and this naturally gives rise to 

 researches of an interesting nature. By means of these very 

 recent works, there is no difficulty in arriving at a very exact 

 apprehension of the present state of this branch of science. 



11, On thk best mode of ascertaining, naming, and classi- 

 fying Fossil Vegetables. 



1. On ascertaining Fossil Vegetables. — As the more minute 

 and delicate portions of vegetable organization have not been 

 preserved among the stratified formations of the earth, we are 

 obliged, in the examination of fossil vegetables, to confine our- 

 selves to the examination of those parts that were possessed of a 

 firmer organization, as, for example, the trunks and stems, the 

 leaves and certain fruits. The more delicate plants in the act 

 of growing, flowers, and the majority of fruits and grains, are 

 not found at all. The more herbaceous plants also, and those 

 most analogous to the confervae, mushrooms and lichens, &c., if 

 they existed at all, have hkcwise disappeared, or are found in a 

 more or less altered condition. 



The ligneous trunks are converted into stone, the result of 

 the gradual substitution of earthy particles for those which 



• Hist, des Voget. Fossiles, in 4to. now appearing in numbers, 

 t Fossil Flora, flvo. Loudon. lias appeared in quarterly numbers since 

 1831. 



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