ILLUSTRATED BY FIGURES. 37 
can be learned from the exhibition of black and homogeneous masses, a por- 
tion exhibiting the regular texture of the plant has been selected. 
Figs. 13, and 14. These represent portions of transverse slices of a fos- 
sil tree found in the Island of Egg, one of the Inner Hebrides. This fos- 
sil is the more interesting, that it appears to prove that certain beds of the 
oolitic series are always accompanied by plants of the higher classes. The 
beds in which it occurs, are so similar to those of Troternish, in the Island 
of Skye, that it is difficult, on minute comparison, to distinguish them. 
According to Messrs SEpGEWick and Murcuison, the Troternish beds 
are the upper strata of the great oolitic series, and resemble the Cornbrash 
and Forest Marble. The stem from which the slice, here partially repre- 
sented, has been taken, was found at the base of the magnificent mural 
escarpment of the Scuir of Egg, where the order of succession is much ob- 
scured by superficial accumulations of incoherent matter. The fossils of the 
lias generally are of a light brown colour, but this is remarkably dark. The 
concentric layers are very distinct, and the longitudinal fibrous structure si- 
milar to that of a recent tree. In the slice, lacune are seen sparsely and 
irregularly distributed. In the discrimination of individual fossil trees, 
much assistance is derived from the colouring, which, however, I have been 
obliged to omit in the figures. The Egg fossil is easily distinguished 
from all others which I have seen, by its deep black colour, and moreover 
possesses a peculiarly beautiful arrangement, better seen with the naked eye 
than with the microscope, and resulting from the distinctness of the medul- 
lary rays. The concentric layers are also very distinct. 
In conclusion, there seems to me no reason to doubt the propriety of re- 
ferring the whole of the fossils figured in this Plate to the Conifere. Fig. 7. 
bears a strong resemblance to Fig. 4. of Plate I., as do Figs. 13, and 14. 
But my object in the present publication is not to speak of generic identi- 
ties, but to attempt the demonstration of ordinal relations. 
