Faloeontology. 331 



is a solitary one ; future researches will probably bring to light 

 other instances of a similar kind. May not these facts be an 

 extension to plants of the recently advanced doctrine regard- 

 ing animals, that species which have had a wide range in space 

 have also had a long duration in time \ or, as it is expressed 

 by those who first brought it forward, — " That the species which 

 are found in a greater number of localities, and in very distant 

 countries, are almost always those which have lived during the 

 formation of several successive systems." The attention of 

 geologists, I believe, was first directed to this highly important 

 observation by Viscount d'Archiac and M. de Verneuil, in their 

 joint paper " On the Fossils of the older Deposites of the Rhe- 

 nish Provinces," read before this Society in December 1841 ; 

 and while these distinguished geologists announced the law as 

 applicable to the oldest fossiliferous beds, Professor Edward 

 Forbes has shewn the extension of it to existing species. He 

 found " that such of the Mediterranean testacea as occur both 

 in the existing sea and in the neighbouring tertiaries, were 

 such as had the power of living in several of the zones in depth, 

 or else had a wide geographical distribution, frequently both." 

 He adds, " the same holds true of the testacea in the tertiary 

 strata of Great Britain. The cause is obvious : such species as 

 had the widest horizontal and vertical ranges in space, are ex- 

 actly such as would live longest in time, since they would be 

 much more likely to be independent of catastrophes and de- 

 stroying influences than such as had a more limited distribu- 

 tion.'' Now we know that the same species of plants are 

 found in the coal-fields belonging to the pala90zoic carbonifer- 

 ous rocks of Europe and of North America, and in regions with 

 diflferences of more than thirty degrees of latitude ; and, there- 

 fore, they may have been able to live through the many vicis- 

 situdes of condition of the earth's surface that must have 

 occurred between the Carboniferous and Liassic periods. 



The plants from the Permian system of Russia, collected by 

 Sir R. Murchison and his fellow-travellers, have been described 

 by Mr Morris, and further illustrated by the remarks of M. 

 Adolphe Brongniart. The species are few, not exceeding 

 sixteen in number. Three of these — Neuropteris tenuifolia^ 

 Lepidodendron elongatum and Calamites Suckotvii — are pro- 



