of Edinburgh, Session 1873-74. 
241 
Monday, 19 th January 1874. 
Principal Sir ALEX. GRANT, Vice-President, in the Chair. 
The following Communications were read : — 
1. Supplementary Notice of the Fossil Trees of Craigleith 
Quarry. By Sir R. Christison, Bart., Hon. Vice-President, 
R.S.E., &c. 
This notice supplements that of 5 th May last, which has been published 
in the Abstracts of the Proceedings of the Society. 
Seven fossils, all apparently belonging to the Pine tribe, and 
either to the same species, or to two closely allied to one another, 
have been uncovered since 1826 in the sandstone of Craigleith 
Quarry. Six are stems of great trees ; and one is a longitudinally 
split section of a large branch, or possibly of another stem. Portions 
of all seven have been traced as still in existence, and have been 
subjected more or less to examination. Of one, the greatest of 
all, about 36 continuous feet, from 12 to 14 feet in girth, have 
been removed in large fragments to the British Museum, and will 
be pieced and erected there. Another, found in 1830, is now 
partly in the Botanic Garden, and will be supplemented by other 
portions at present in the Museum of Science and Art, so as to 
make a nearly perfect fossil stem 30 feet in length. A third, 
nearly 9 feet in girth, has been sliced and polished, to show its 
structure on the great scale, and will be exhibited in the British 
Museum, the Edinburgh Museum, and the Edinburgh Botanic 
Garden. 
The composition of all these great fossils is substantially the 
same. The great mass of each consists of carbonate of lime, 
carbonate of magnesia, carbonate of protoxide of iron, and free 
carbon, *the proportions varying in different parts of the same 
fossil. The iron-carbonate and charcoal vary most in their amount. 
The charcoal, which is left after the action of diluted acids, some- 
times without any other insoluble residuum, seems to form three 
per cent, of the mass, unless when collected, as it often is, in 
