of Edinburgh, Session 1873-74. 
377 
2. Note on the Submerged Fossil Trees of Granton Quarry. 
By Sir R. Christison, Bart., Hon. Y.P., R.S.E. 
It may interest those who are acquainted with the history, 
structure, and composition of the Craigleith fossil trees, described 
in the two papers recently read to this Society, to learn that an 
opportunity has occurred for examining comparatively specimens 
from the submerged fossil trees of Granton Quarry. The speci- 
mens were preserved by Mr Hawkins, engineer of the Granton har- 
bour, and have been, through his kindness, not only subjected to 
examination, but also presented for preservation to the Botanic 
Garden collection. 
It turns out that the microscopic structure and chemical com- 
position of the greater of the two Granton fossils are precisely 
the same with the structure and composition of the fossils of 
Craigleith, two miles distant. The embedding rock is also the 
same in composition, whether in its pure state, or where altered by 
percolating water. That is, the microscopic structure of the 
Granton fossils appears to be that of the pine tribe; and the 
fossilising material consists of the carbonates of lime, magnesia, 
and iron, all in notable proportion; and while the fundamental rock 
of the quarry is a very pure quartzy sandstone, without any binding 
calcareous carbonate, many masses may be seen among the blocks 
raised many years ago from the quarry, but not made use of, which 
like similar altered specimens from Craigleith, have their fracture, 
colour, and toughness changed by the same material which has 
fossilised the trees. In the fossils, too, there is the same three 
or four per cent, of charcoal left after the solvent action of acids 
on the fossils of Granton as on those of Craigleith. 
That part of Mr Witham’s fossil of 1830 which lay in front 
of the Museum of Science and Art, has now been removed to the 
Botanic Garden, to be added to the lower part of the trunk of 
which it is the continuation. In separating two of the segments, 
a cavity was found which contained a matter like charcoal, some 
fragments of which even presented the fibrous appearance of 
charcoal to the naked eye; and Mr Sadler, of the Botanic Garden, 
has ascertained that some of these fragments show before the 
