468 Notices of Memoirs — Land-plant in the Silurian. 
sphere, which is small, and placed somevvhat jauntily on one side. 
At one time it was in all probability much larger, and was then 
drawn fartber down over our northern regions than it is at present ; 
but so far as I have seen, many of the markings it may tben liave 
made can also be explained by more modest assumptions ; wbilst 
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 eise not suffi- 
ciently convergent in their character. 
(To be continued in our next Number.) 
3STOTICES OIF 1 MEMOIBS. 
I. — On the Discovery of a Land-plant in the Middle Portion 
of the Silurian Strata. By M. G. de Saporta. (Comptes 
Bendus de l’Academie des Sciences, tom. lxxxv. No. 10.) 
T HE 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 slat.y-schists of Angers, 
and from the zone of Calymene Tristani, which fumishes evident 
traces of a tolerably large fern. The impression is in a fair state of 
preservation ; the vegetable substance is replaced by sulpburet 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 dichotomons, with- 
out a median vein properly so called, places this fern amongst the 
Neuropteridce ; it calls to mindthe genera Cyclopteris and Palaopteris 
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 Algae of a doubtfiü 
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 rieh 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 
Palseozoic epochs, assured me, three or four months ago, that he 
had collected on his side, terrestrial plants, and particularly ferns. 
