70 SKETCH OF THE LIFE AND CHARACTER 
gued that these fossil trees must be now on the 
spot where they grew, since they are perpendicu- 
lar to the strata of coal on which they rest; for 
had they been drifted to their present situation, 
he contended it was in the highest degree impro- 
bable, they should all have remained so regularly 
disposed at a similar angle in the same direction 
to the horizon. He further endeavoured to show, 
from an examination of structure, that most of 
these were hard-wooded trees, which had become 
hollow through internal decay, in the same way 
as trees of a similar structure become so in tro- 
pical climates at the present day; and that the 
hollow cylinders thus produced, formed a sort of 
matrix within the carbonized bark for a mass of 
sedimentary deposit, which presents in its now 
exposed state, an exact cast of the original tree. 
At the close of this paper he threw out two sug- 
gestions for the consideraticn of future inquirers ; 
(1.) Whether from the size of these trees and 
their probable rate of growth in a tropical climate, 
it be possible to draw any inference as to the 
minimum of the period which it would require to 
form a mass of vegetable matter, yielding a coal- 
bed nine inches thick; and (2.) Whether the 
amount of shrinkage can be approximated, which 
