﻿468 Notices of Memoirs — Land-plant in the Silurian. 



sphere, which is small, and placed somewhat jauntily on one side. 

 At one time it was in all probability much larger, and was then 

 drawn farther down over our northern regions than it is at present ; 

 but so far as I have seen, many of the markings it may then have 

 made can also be explained by more modest assumptions ; whilst 

 not only its tracks, but also of the allies it would have summoned 

 into being, we yet need proof of their existence. 



Various causes as at present have in past times been in action, and 

 the results of one may often have obliterated those of others, which 

 renders the tracing of phenomena to their origin a matter of 

 difficulty, because our data are either antagonistic or else not suffi- 

 ciently convergent in their character. 



[To be continued in our next Number.) 



isTOTiOES OIF" isd::E3vcozias. 



I. — On the Discovery of a Land-plant in the Middle Portion 

 OF THE Silurian Strata. By M. G. de Saporta. (Comptes 

 Eendus de I'Academie des Sciences, tom. Ixxxv. No. 10.) 



THE discovery that I am about to announce to the Academy is 

 quite new. On my journey to Caen, three days ago, I received 

 from Prof. Moriere, a slab, coming from the slaty-schists of Angers, 

 and from the zone of Calymene Tristani, which furnishes evident 

 traces of a tolerably large fern. The impression is in a fair state of 

 preservation ; the vegetable substance is replaced by sulphuret of 

 iron, and many of the outlines are broken or torn, as if the plant 

 had suffered from a long sojourn at the bottom of the waters. A 

 long stem is distinguishable, along which the pinnules, attenuated 

 towards their point of insertion, are attached by a subsessile base. 

 The venation, composed of very fine veins, often dichotomous, with- 

 out a median vein properly so called, places this fern amongst the 

 Neuropteridce ; it calls to mind the genera Cyclopteris and Palmopteris 

 in the Upper Devonian or Lower Carboniferous series ; but the 

 species I now record cannot be confounded with any of those 

 hitherto described. The Silurian of Europe having as yet, in point 

 of vegetable remains, only furnished some AlgfB of a doubtful 

 character, we may conclude this fern from the slaty-schists of Angers 

 to be the oldest terrestrial plant that has been met with on our 

 continent. The existence of the family of ferns is thus carried back 

 to a period more remote than one would have supposed. The origin 

 itself of vegetation will be thrown back far beyond the Silurian, 

 since the fern from Angers, by reason of its affinity with the 

 Carboniferous Neuropteris, seems to indicate a flora already rela- 

 tively rich and complex, and far removed from the beginning of 

 plants, and the first apparition of life. 



I should add that the learned Leo Lesquereux, who, in America, 

 pursues his researches on the plants of the Carboniferous and 

 Pala30zoic epochs, assured me, three or four months ago, that he 

 had collected on his side, terrestrial plants, and particularly ferns, 



