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PLANT REMAINS IN NORTH AMERICA. S3
scribed a singular collection of coniferous fossils from strata of Calca-
reous age occurring in the Belgian province of Hainault, but with
them is associated a Cycad belonging to an extinct tribe of the Order.
No trace whatever remains of these Cretaceous plants in the existing
flora of the regions where they are found. A corresponding/tfc/es of
vegetation can be found at the present day only in tropical regions,
and to a considerable extent the same may be said of the vegetation
of the Tertiary strata. The tropical character is not so strongly pro-
nounced, but the Orders and genera represented are more southern
forms than those now living in Europe. Two or three Palms, species
of Smilitx, Cinnamonium, Llquidcwibar, Llriodendron, etc. ; numerous
forms oi Proteacea, referred to the modern genera Banksla, Dryandra,
Hcikea, and Persoonia, and coniferous forms belonging to Sequoia,
Tcixodmm, Glyptostrobiis, Frenela, etc.,—form a group of plants the mo-
dern representatives of which, must be sought sometimes in America,
sometimes in Australia, and at others in Asia or Africa, but least of all
in Europe, and, in the few cases that do occur in Europe, only in
the Mediterranean region of the Continent. The Tertiary flora is
much further removed from the existing vegetation of Britain than
it is from the Cretaceous flora, and yet from this it is very clearly
distinguished.
In America the relations of these successive floras are very different.
Many genera ai'e common to each of the three periods, and no very
mai'kedline of distinction can be drawn between either of them. Pro-
fessor Newberry has just given us the means, of forming an approximate
estimate of the facies of the two extinct floras,* in a recent Essay, whicli,
besides containing much new and original labour, gives a narrative of
all that has been done before. The plants found in Cretaceous rocks
were at first believed to be of Tertiary age, on account of the modern
character of the genera found among them. The true stratigraphical
position of the rocks in which they occur has, however, been esta-
blished, beyond a doubt, from the discovery of unmistakable Cretaceous
shells in them, like Grypluea Pitcheri and Tnoceramus prohlematictts.
The forms enumerated by Newberry contain only a few, which have
disappeared from North America, such as Cinnamomum, Clssus, Ficus,
* Notes on the Later Extinct Floras of Korth America, with description of
some new species of Fossil Plants from the Cretaceous and Tertiary Sti-ata.
Annals of the Lyceum of Xat. History in New York, vol. ix. 1868.