96 THE ROYAL SOCIETY OF CANADA 
notable feature in “ Maritime” plants. With this feature is sometimes 
associated the occurrence of succulent roots; such seemingly was the 
nature of the underground support in Himantophyton and of Psilophy- 
ton. Sir Wm. Dawson also says the root was a Rhizome or subter- 
ranean holdfast, not a slender vascular root. Ginkgophyton Leavitti 
of the Dadoxylon sandstone also had a rhizome, but this was probably 
a species of the river sands. The Arthrostigma of Beaver harbour was 
as intimately associated with Himantophyton as the Devonian species 
of this genus was with Psilophyton. So I think we may look upon these 
three genera as of “Maritime” habit, though the last named had a 
wider range of habitat, if one should include all the forms that have been 
referred to it. 
The next ecological grouping to which I shall refer is that of the 
plants that characterize the Dadoxylon sandstone and are autocthone 
in that group. Some of these are found to pass by varieties or otherwise 
to the next group, but nevertheless they form a characteristic grouping 
which does not extend in its entirely to a soil with different conditions 
of moisture and composition ete. They may be called Fluvial and are 
such as grew on sandy shores and river banks, and in the shallow pools 
behind such banks. Such pools or lagoons are apt to dry up when the 
river becomes low in the dry season, and its plants would be fitted to 
stand a certain amount of drought. To this group we would refer all 
the Silurian plants of the strata in the St. John and Lepreau basins 
below bed 2 of Prof. C. F. Hartt’s section. A part of these plants, as 
those of Calamites and Lepidocalamus, are from the coarser sands, but 
others, as Asterophyllites and Annularia, are characteristic of the sandy 
clay of the shallow ponds described above. 
In the plants collected from beds No. 2 to No. 8 of Professor Hartt’s 
section he found a different grouping of plants; these are chiefly of 
genera that are abundant in the dense vegetation of the Coal measures, 
and consist largely of Pteridosperms; among which occur the familiar 
names of Neuropteris, Sphenopteris Pecopteris, and Alethopteris, but 
more widely distributed and more plentiful than these is Cordaites, re- 
cognized by its broad, palm-like leaves. There can be little question 
that these were subjected to conditions of growth similar to those that 
affected the plants of the Coal measures, but that they did not produce 
coal beds of economical value may have been due to the absence of 
Lepidodendra and the rarity of Sigillariz which possessed an abundance 
of hard tissues. It cannot be said however, that coal seams are en- 
tirely absent, for there is one in the Lepreau basin several feet in thick- 
ness; the coal, however, is heavily charged with ash, it is an anthracite 
and so thoroughly powdered by movements of the strata that the econo- 
mical value it may once have possessed has been destroyed. 
