ILLUSTRATED BY FIGURES. OT 
Fig. 14. represents the Gymnospermous Phanerogamic stem, shewing a 
central pith, woody layers separated by a condensed line, and consisting of 
elongated cellular texture arranged in regular series; medullary rays which 
run continuously from the first or inner layer to the bark, new ones, com- 
mencing at the line of separation of the layers, being added; and, finally, 
the bark, consisting of several layers or portions. 
Fig. 15. represents the Dicotyledonous stem, shewing a central pith, 
woody layers separated by a condensed line, elongated cellular texture in se- 
ries, large regular openings of vessels, medullary rays, which run continuous- 
ly from the pith to the bark, new ones commencing at the lines of separa- 
tion of the layers being added, but all more or less flexuous, being bent 
round the vascular apertures; and, finally, the bark. 
In structure, the stems of the Dicotyledonous Phanerogamic, and Gym- 
nospermous or Polycotyledonous Phanerogamic plants, are more allied to 
each other than those of the Monocotyledonous Phanerogamic plants are to 
either; and in this order I have represented and explained them. 
PLATE II. 
THE figure here represents a transverse section, viewed by reflected 
light, and diminished one-half, of a portion of one of the Fossil Vegetables 
mentioned at p. 14. as occuring near Lennel Braes, on the Tweed, in Ber- 
wickshire. Their situation in the lower bed of shale has been already men- 
tioned. 
These stems are generally distorted and flattened. They are invested 
with an external coat of carbonized matter, in all respects resembling the 
purer kinds of common coal. It is difficult to ascertain their length, as 
they have been fractured at short intervals. The highest stem which I 
have been able to obtain, is not much above four feet, and the lowest part 
of it about six feet in circumference. No two stems, or portions of stems, 
possess the woody appearances in their interior alike, some retaining them 
D2 
