1835.] De Candolles Introduction, Sfc. 67 



because their seeds or sporules are so minute that they are scarcely 

 visible, and might be easily carried over seas and mountains. Thus 

 the cold zones of the two hemispheres, where these plants predomi- 

 nate have many specie, in common, and M. De Candolle the father, 

 has sometimes remarked upon the trunks of trees in the promenade 

 of Quimper-Corentin, on the side exposed to the south-east wind, 

 two Jamaica lichens, Sticta crocata, and Physcia Jlavescens. 



The book which treats of vegetable fossils is filled with curious 

 observations, extracted principally from the Prodromus of M. 

 Adolphe Brongniart, which appeared in 1818. This author divides 

 the primitive formations, or those which contain no trace of orga- 

 nized beings into four great categories, each of great length, and 

 the secondary with the tertiary into four formations divided into 

 fourteen distinct epochs. In the first of these formations which 

 extends from the first transition beds to the end of the coal deposit, 

 there exists a great proportion of cryptogamic plants, especially 

 arborescent Fuel, Equisetacece, and Lycopodiaceae, of which we 

 can scarce find any analogies at the present time in the warmest 

 climates. 



The second formation, which is least known, possesses rather more 

 phanerogamous than cryptogamous plants ; in both, different from 

 those of the first period. The third contains a very great proportion 

 of Cy cades, a family allied to cryptogamia, but which does not exist 

 at the present day. Lastly, comes the most recent epoch in which 

 the phanerogamous plants predominate, especially the dicotyledo- 

 nous. The results which these facts ascertained in our time pre- 

 sent, are numerous, and very remarkable. We prominently observe 

 that the vegetables contemporaneous with the first formation, are 

 very different from those which exist at present ; and that those 

 which have succeeded them in the two other periods, have no more 

 resemblance to the first than to each other ; so that there has been 

 a successive creation of families, genera and species up to the fourth 

 and last period, which presents vegetables analogous to those now 

 existing, and being formed of a greater number of organs than 

 the preceding, are consequently more perfect. There is here a 

 striking correspondence between the two organic kingdoms ; for ver- 

 tibrated animals, of which man is chief, only appear in the last 

 formation; and in the two kingdoms, we find in our northern 

 climates beings, which could not be propagated at present, because 

 the temperature appears to have been formerly higher than it is at 

 present. 



Several interesting points have been omitted by the author, such 

 as the source of our different species of cultivated grain, which we no 

 longer find in a wild state, but which have not been produced by 

 cultivation, as is proved by the fact, of wheat having been found in 

 Egyptian mummies 3000 years old, * in almost a perfect state of 

 preservation, and equal in size to that cultivated among us. 



The most imperfect part of the work is that which treats of the 

 superior phenomena, which escape our physical explications, and 



* Records of General Science,.!. 446. 



f2 



