270 
SILURIA. 
[Chap. XI. 
whorls of smaller twigs, like their living representatives. Again, large 
branching woody roots, f. 5, but destitute of superficial markings, appear 
to have belonged to the same Trees, and are often several feet long. With 
these occur very many specimens of a Lepidodendron, f. 4, with scaly, short 
leaves (L. nothum, Unger ?, or a species very like it), — and a Lycopodites, 
f. 3, with long prostrate stems and secund or one-sided foliage, like that of 
the common Lycopodium clavatum. This last may of course be of quite a 
different natural order, and even Coniferous; but its general resemblance 
alone is implied in the name. 
Linear and branched (dichotomous) fragments *, some of them smooth, 
f. 1, 2, and destitute of all markings, have also been found, whilst others, 
like them, are covered with small tubercles in quincunx order, and are 
probably the roots of Lepidodendron, f. 4. 
The probability of the smooth forms, f. 1, being also roots is very strong. 
Similar bodies occur in beds of the Upper Devonian series in North Devon 
and the South of Ireland, and in such a position with regard to the fluted 
stems of Knorria, with which they are associated, as to lead to the belief 
that they are the rootlets of that Plant. The larger ones have even mark- 
ings similar to those of the main stem. 
This probability is strengthened by finding with them similar linear spe- 
cimens which bear tubercles or excrescences at their tips and along their 
sides, very like those on the roots of Leguminous Plants and many of the 
Conifers f . The latter is the more probable analogy. 
Hugh Miller has indeed figured a similar fossil $ as probably belonging 
to an ancient marine Plant resembling the Zostera, and has reasonably 
speculated on the existence of wide fields of such vegetation on the muddy 
shores of the Old Eed period; but our more perfect specimens justify 
the belief above stated, and as yet there is no evidence of any marine 
Plant in the Caithness schists. The vegetable remains have evidently 
been swept from adjacent lands into the sea inhabited by the Fishes above 
described §. 
The flora, on the whole, is analogous to that of the Carboniferous forma- 
tion, though distinct as to species. In short, there were large Coniferous 
Trees (with whorls of branches and a structure like that of the Norfolk- 
Island Pine), Lepidodendron, Lycopodites, and Ferns. That these grew 
near the coast and were entombed in the shallows of a muddy shore 
(sometimes in lakes or lagoons, as, perhaps, in the Upper Old Eed period) 
seems proved from their good preservation and from the nature of the 
matrix, which, moreover, is indented by the burrows of "Worms (see f. 2) 
like those made upon the shores in our own day. 
As we advance still higher in the series, or into the strata which overlie 
* See alao Miller's ' Footprints,' p. 193. $ It Bhould also be remembered that Cepha- 
t Dr. J. D. Hooker, Proc. Linn. Soc., No. 58, laspis and Pteraspis, both typical ' Old Eed ' Fish, 
p. 355*. are found with marine forms at Inidlow. 
I Testimony of the Rocks, p. 425. 
