ME. E. W BINNEY ON SOME LOWEE-COAL-SEAM EOSSIL PLANTS. 
597 
still his information is confined to two plants. These, no doubt, have contributed by their 
remains in a great measure to form the two seams of coal in which they were found, as 
is evident from the abundance of Sigillaria-roots now found in floors of the beds. In 
addition to this fact, the Halifax Hard or Gannister seam yields the Sigillaria vascularis 
as by far the most common plant found in it. 
The large specimens Nos. 2 & 3, now described and figured, some persons may doubt 
as being the older forms of the Sigillaria vascularis described by me some years since in 
the Geological Society’s Journal previously quoted, as well as the medium-sized specimen 
No. 8 given in Plate XXXV. fig. 5 of this memoir; but the one has been traced 
gradually passing into the other so as to leave no doubt on this point, and the internal 
structure is unquestionably the same both in the large and small plants, after making 
due allowance for the greater age of the former. 
The general opinion of botanists and geologists, that Sigillaria was a hollow and 
succulent plant, no doubt arose from the flat specimens generally found compressed into 
thin plates in indurated clays or shales. The same view was taken with regard to 
Calamites , owing to their being nearly always found in a similar condition ; but it is 
now well known that many specimens of Calamites are nothing more than the casts of 
the central axis of a hard-wooded tree with concentric rings, the whole of which has in 
most cases disappeared and left no trace of its former existence. Now, although till 
the discovery of my specimens few, if any, large Sigillaria had been found exhibiting 
structure, it has been shown that the late Mr. Bowman, an eminent botanist, many 
years since pronounced the Dixon Fold fossil trees to be large Sigillarice and hard- 
wooded dicotyledonous trees with heavy tops, and this he inferred chiefly from the size 
and form of their roots. Long after the last-named author’s death, Dr. Dawson, in 
1859, as previously quoted, was inclined “ to suspect that some of the described species 
of conifers of the coal may be the woody axes of large Sigillarice , or at least of trees 
approaching quite as nearly to those plants as to modern conifers.” Although my 
specimens do not altogether support Dr. Dawson's views as to the woody axis he no 
doubt refers to, namely, the internal radiating cylinder and not the outward one, 
which he terms a very thick cellular inner bark, his opinion is entitled to considerable 
weight as to Sigillarice being hard-wooded trees, he having paid great attention to the 
different structures found in the charcoal now met with in our coals, the floors of 
which so constantly testify to the presence of Sigillaria in the form of roots, and the 
great part it contributed to their formation. The size of the external cylinder of this 
plant, when compared with its internal one, is so much greater, that by far the larger 
portion of the coal must have been derived from the former. It is this part of the fossil 
tree that so generally divides into rectangular masses, and not the small internal 
cylinder evidently alluded to by Dr. Dawson, as any person who has examined many 
large specimens will well know. 
Specimen No. 2 probably may not be considered as so marked an example of the 
genus Sigillaria , owing to the small size and indistinctness of the cicatrices left by the 
5 m 2 
