632 
DR. J. W. DAWSON ON ERECT TREES CONTAINING ANIMAL 
no local restriction in this matter, unless the scarcity of the erect trees toward the end 
of the reef may indicate a margin of the forest in that direction. 
The trees range in diameter from a foot to nearly 3 feet, the ordinary diameter 
being about 18 inches. The measurements of diameter were made at a short distance 
above the base, where the trunks became approximately cylindrical. The extreme 
diameter of the largest tree at the base was 3 feet. The measurements of height 
refer to the actual condition of the trees. The maximum height of trees which had 
o 
lost nothing by denudation is 9 feet; but several of those now of less height may, 
previously to the modern denudation of the beds, have been as tall as any of the 
others. 
So far as can be ascertained, all the trees affording amphibian remains as well as the 
others standing erect with them, belong to the genus Sigillaria in its wider sense, or 
to the family Sigillarice. Those retaining markings have the characters of the broad- 
ribbed species of Sigillaria proper, like S. reniformis and S. Brownii, which seem to 
have been among the largest trees of the coal-period, and those best fitted, by the 
density and indestructibility of their outer bark, for retaining an erect position. 
Trunks and branches referable to the subdivisions Rhytidolepis and Favularia* and 
also trunks of Lepidqfloyos, occur in a flattened condition in the black shale; and these 
as well as Cordaites must have constituted portions of the same forest, though none 
of them endured long enough to become repositories of amphibian remains. All the 
erect trees, so far as observed, had roots of the Stigmaria type. 
It is deserving of remark in this connexion, that the circumstances of the growth 
and entombment of this forest entirely contradict those theories as to Sigillaria and 
Stigmaria which suppose that these plants grew in water or on submerged areas. In 
the present instance the surface on which the trees grew, now represented by the 
6-inch coal, must have been underlain by several feet of peaty matter with prostrate 
trunks of trees, and no remains of aquatic animals. The forest contained not only 
Sigillarice of different species but Lepidojloyos. Cordaites , and Ferns. When the area 
was submerged this vegetation was killed, while plants like Sphenophylluin, which 
could grow in water, apparently took its place, and were in turn replaced by Sigillarice 
and Calamites when the area again became land. Further, when the reptiles fell into 
the erect trees the surface on which they walked, though subject to inundations, must 
ordinarily have been several feet above the drainage level, otherwise the hollow trees 
would have remained full of water. 
No remains of any aquatic animals were found in the trees holding amphibian 
remains, unless certain minute annulated bodies, doubtfully compared by Dr. Scudder to 
leeches, can be regarded as of this character. The vegetable matters present consisted, 
first of the decayed material of the interior of the trunk itself, and, secondly, of frag¬ 
ments which had fallen into or been drifted into the trees after they became hollow. 
Most of these were pieces of bark and wood, but leaves of Cordaites were not un- 
* See ‘Acadian Geology,’ p. 432-3. 
