86 ON THE TERTIARY FLORA OF THE ARCTIC REGION. 
leaves. Ihold the formation to be grauwacke, although I am prompted 
to offer this opinion, not from the very imperfectly preserved plants, 
but from an empiric view which a long study of this formation has 
enabled me to form; and I should not allude to it at all, if it were 
not that my hint might lead to the discovery of its true position, and 
then to that of the productive coal-beds so frequently associated with it. 
On returning to the Tertiary formation of the above-named regions, 
we find that we have fragments of seventeen plants (of which, how- 
ever, only twelve can be made out with certainty); they have been 
collected in nine different places, the distances of which from each 
other are however unknown to me, so that I have no opinion about the 
range of this formation. At the same time, a relationship amongst 
them cannot be gainsaid, established as it is by two species, common to 
nearly all localities, and justly entitled on account of their wide, already 
explained range, to be regarded as the leading plants of the Miocene 
formation, viz. Sequoia Langsdorfi and Taxodium dubium, which, in 
conjunction with the other species, place the Miocene age of these 
strata beyond doubt. True, the materials at my disposal are not suf- 
ficient for a more exact classification ; but of the collection enumerated 
sub No. 2, consisting of ten specimens, it may perhaps be said that 
the occurrence of willows and other species allied to the flora of 
Oningen and Schosnitz justifies us in regarding them as rather more 
recent than the others, and perhaps as belonging to the upper Miocene 
strata. Finally, it is hardly necessary to add that in all these places a 
much greater abundance of fossil species must exist, and that, by 
further investigation, the Tertiary flora of Russia will receive con- 
siderable additions. 
On reviewing the extensive range of the flora of the Miocene forma- 
tion already ascertained to exist in the Arctic and subarctic region, in 
the Aleutian Islands, Greenland, Iceland, and Kamtchatka, perhaps also 
extending over the northernmost parts of America, North Siberia, 
and the islands of the Iey Sea (whence may be derived fragments of 
lignite, here and there mixed with amber, which occur, according to 
Lapechin,* Georgi,t and Schrenk, on all the coasts of the Arctic Ocean), 
* Reise, vol. iv. p. 106. 
7 ' Beschreibung des russischen Reichs,’ vol. i. pp. 333, 334. 
