ANNIVERSARY ADDRESS OF THE PRESIDENT. 211 



for the anomalous position of these coal plants; "A I'epoque ou la 

 formation du lias se deposait en Europe, notre globe presentait tres- 

 probablement deux regions tres-diverses par leur climat et par les 

 vegetaux qui y croissaient. L'une comprenait I'Europe et peut- 

 etre toute la zone temperee, et etait habitee par des vegetaux fort 

 differens de ceux qui y croissaient a une epoque plus reculee, et 

 qui avaient donne naissance aux couches de houille ; I'autre s'eten- 

 dant sans doute sur les parties plus chaudes du globe, etait encore 

 couverte des menies vegetaux qui, dans des temps plus anciens, 

 avaient habite la region europeenne, et forme les depots houillers. 

 Les vegetaux de cette partie du globe pouvant dans certaines cir- 

 constances, etre transportes dans les regions plus temperees, au- 

 raient donne lieu a ces anomalies apparentes que presentent les 

 terrains d'anthracite des Alpes qui, d'apres les observations geolo- 

 giques et zoologiques, appartiennent a I'epoque de formation du 

 lias, et dont les vegetaux sont cependant les memes que ceux du 

 terrain houiller." This theory therefore admits that the same spe- 

 cies of plants existed through the whole series of ages that passed 

 from the time of the deposition of the carboniferous series to that of 

 the lias; that they and Belemnites were co-existing, but in different 

 regions. It is not very easy to conceive how such delicate vegetable 

 bodies should be drifted the vast distance between a tropical and 

 temperate zone, to form parts of thin continuous strata thousands 

 of square miles in extent, in successive layers of great thickness on 

 the same spot, in the depths of the sea. 



It is extremely improbable that this case in the Tarentaise 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 regarding 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 tliose 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 Deposits of the Rhe- 

 nish Provinces," read before this Society inDecember IS^l; and while 

 these distinguished geologists announced the law as applicable to tlie 

 oldest fbssiliferous beds. Professor Forbes has shown the extension 

 of it to existing species. He found " that such of the Mediterranean 

 testacea as occur both in tiie 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, fre- 

 quently both." He adds, " The same holds true of tiu^ testacea in 

 the tertiary strata of Great Britain. Tiie cause is obvious: such 

 species as had the widest horizontal and vertical ranges in space, are 

 exactly such as would live longest in time, sii^ce tliey would bo much 

 more likely to be independent of catastrophes and destroying influ- 

 ences than such as had a more limited distribution." Now we know 



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