282 NOTICES OF THE MEETINGS [March 18, 
waves and the weather. Originally the reverse was doubtless true, 
for in the existing delta of the Mississippi the clays in which innu- 
merable roots of swamp trees, such as the deciduous cypress, ramify 
in all directions, are seen to withstand far more effectually the ex- 
cavating power of the river or of the sea at the base of the delta, 
than do beds of loose sand or layers of mud not supporting trees. 
This fact may explain why seams of coal have so often escaped 
denudation, and have remained continuous over wide areas, since 
the roots, now turned to coal, which once traversed them would 
enable them to resist a current of water, whilst other members of 
the coal formation, when in their original and unconsolidated state 
consisting of sand and mud, would be readily removed. 
The upright trees usually inclose in their interior pillars of sand- 
stone, or shale, or both these substances alternating, and these do 
not correspond in the thickness of their layers, or in their organic 
remains, with the external strata, or those enveloping the trunks. 
It is clear therefore that the trees were reduced while yet standing 
to hollow cylinders of mere bark, (now changed to coal,) into which 
the leaves of ferns and other plants with fragments of stems and 
roots were drifted together with mud and sand during river inunda- 
tions. The stony contents of one of these trees, nine feet high and 
twenty-two inches in diameter, on being examined by Messrs. 
Dawson and Lyell yielded, besides numerous fossil plants, some 
bones and teeth which they believed were referable to a reptile; but 
not being competent to decide that osteological question they sub- 
mitted the specimens to Dr. Jeffries Wyman of Harvard University 
in the United States. That eminent anatomist declared them to be 
allied in structure to certain perennibranchiate batrachians of the 
genera Menobranchus and Menopoma, species of which now inhabit 
the lakes and rivers of North America. This determination was 
soon afterwards confirmed by Professor Owen of London, who 
pointed out the resemblance of some of the associated flat and sculp- 
tured bones, with the cranial plates, seen in the skull of the Archego- 
saurus and Labyrinthodon.* In the same dark-coloured rock, Dr. 
Wyman detected a series of nine vertebre, which from their form and 
transverse processes he regards as dorsal, and believes them to have 
belonged to an adult individual of a much smaller species, about six 
inches long, whereas the jaws and bones before mentioned are those of 
a creature probably two and a half feet in length. The microscopic 
structure of these small vertebree was found by Professor Quekett 
to exhibit the same marked reptilian characters as that of the larger 
bones. 
The fossil remains in question were scattered about the interior 
of the trunk near-its base among fragments of wood, now converted 
into charcoal, which may have fallen in while the tree was rotting 
* Professors Wyman and Owen have named the reptile Dendrerpeton Aca- 
dianum, Acadia being the ancient Indian name for Nova Scotia. 
