30 OBSERVATIONS ON FOSSIL VEGETABLES, 
plant here represented, and the recent plants; but in the former, there is 
no appearance of the concentric lines by which the woody layers of the lat- 
ter are separated. The portions represented are chiefly calcareous ; but in 
some fragments, in which the cavities have been filled with siliceous matter, 
there is a distinct appearance of these concentric lines, as may be seen in 
Fig. 9, Plate VI. by which is represented a very regular portion of the 
same fossil. The want of them in the calcareous portions, may probably 
be owing to the more advanced state of decomposition ; and in all, the re- 
semblance to the Conifere is so striking, and the texture approaches so closely 
to that of these plants, that I cannot hesitate to refer the fossil in question 
to the Gymnospermous Phanerogamice class. 
In the year 1826, an enormous trunk was exposed in the lowest bed of 
Craigleith Quarry, near Edinburgh, at a depth of upwards of 136 feet. The 
length of this trunk was 36 feet, and its diameter at the base 3 feet. It lay 
in a nearly horizontal position, corresponding with that of the stratum of hard 
white sandstone, in which it was imbedded. Externally, it was marked with 
irregular longitudinal grooves and prominences, and was encased in a layer of 
coaly matter, being probably the altered remains of the bark. No branches 
were observed. Internally, it exhibited in some places an irregular fascicu- 
lar structure, of a dark grey colour, with reticulations of carbonaceous mat- 
ter. The cracks and fissures were filled with calcareous spar, and the ir- 
regular cavities which it presented were lined by crystals of pearl-spar. 
An analysis of a portion of this plant made by Mr Nicot, afforded the 
following result : 
Carbonate of.Wime,. v3) =< .: otcwrete ee) OO 
Oxidevot Tron eee YE Ie ee AS 
Taming. 72ers) oe ciphhe ned. 
Carbonaceous matter). -) sim 1-5.) 9 
Loss, RRA SS 2 Geena. 33 
