REMAINS IN THE COAL-FORMATION OF NOVA SCOTIA. 
633 
common, and there were numerous specimens of the little nutlets which I have else¬ 
where named Trigonocarpum sigillarice * and which must he fruits either of Sigilhtria 
or of Cordcdtes. Pinnules of Alethopteris lonchiticcc were also occasionally met with, 
and fragments of Catamites . In one tree there occurred so large a mass of aerial roots 
of the type of Psaronius , as to render it probable that these roots may have grown in 
the interior of the decaying tree. 
With reference to the mode of occurrence of the animal remains, it is to be observed 
that from the manner of their entombment all the bones of each specimen must be 
present in the matrix. On the other hand, having dropped asunder on decay of the 
soft parts, and having been liable to disturbance by water dripping into the trunks, 
they are often much displaced. In some instances, also, they have evidently fallen 
into the crevices of loose vegetable matter, afterwards consolidated. Besides this, the 
original inequality of the surfaces of deposit has been increased by the effect of 
pressure in depressing the centre, so as to give a basin-form to the layers and to 
produce a certain amount of displacement at the sides. The effect of this is increased 
by the circumstance that some of the amphibia seem to have crept close to the sides 
of the cavity in which they were imprisoned, and to have died in that position, so 
that their bones lie close to the bark, and in the portion of the deposit most bent by 
pressure. It is thus difficult to collect the whole of the bones belonging to a skeleton, 
and impossible to expose some of them without destroying others. I have' been 
obliged, in consequence, to endeavour to secure and expose the more important por¬ 
tions of the skeleton in as perfect condition as possible, and in many instances it has 
proved possible to recover only a portion of the bones. The state of preservation of 
the remains is very different in different layers. In some cases considerable portions 
of the cuticle remain in a carbonised state ; this has occurred when carcases have been 
quickly covered with moist debris, or permanently water-soaked, so that the soft parts 
could become carbonised instead of decaying away. These portions of cuticle are 
unfortunately not laid out flat, so as to show the form of the animal, but much folded 
and crumpled ; and it would seem that where the cuticle has been thus preserved the 
bones have been specially liable to decay. The bones are often much softer than the 
matrix and of a brownish colour, but in some instances they are quite white and in 
excellent preservation. On a few of the surfaces they have been partially removed by 
the percolation of water. Their cavities are usually occupied with calcite, but some¬ 
times with pyrite. When sliced they generally show their microscopic structure in a 
good state of preservation, though the presence of hard grains of pyrite in the softer 
bone often makes it difficult to prepare satisfactory slices. In a few cases hones of 
small amphibia and shells of Pupa vetusta have been found included in the mineral 
charcoal which forms the lowest layers in the trees, as if these animals had crept into 
the interstices of the fragments of decaying wood and bark. 
# ‘ Acadian Geology,’ p. 477. 
4 M 2 
