84 
Low Moor could not have lived for the enormous time 
necessary for the deposition of all these surrounding strata, 
if not quickly deposited. It makes no difference whether 
the tree grows from the black bed coal, or is floated as a 
snag, with its heavy roots keeping it upright.* 
I think the most consistent theory to illustrate the forma- 
tion of coal is in the low marshy islands, or level delta, in 
the mouths or estuaries of large rivers, similar to the 
Mississippi and Ganges, whose deltas are forming more 
than 300 miles out in the ocean, in a basin-shaped depression, 
as if the centre had receded. That it has been an 
extremely quiet deposit is evinced from there being no 
water-worn pebbles as large as an ordinary pea. Again, 
that the forests and under-wood have frequently grown 
on or near the place where they were submerged, there 
is I think sufficient evidence ; as also that the vegeta- 
tion was only partially decayed ; and few evidences occur of 
a force of stream to float vegetable matter anything like the 
timber rafts of some of the large rivers of the present day. 
If there had been a sufficient force of stream it would have 
brought coarser materials than we find in our shales. By a 
careful examination, I believe it is quite possible to prove 
what coal is deposited from water, which is removed a short 
distance from where it grew ; and what has been embedded, 
comparatively dry, on the very place where it flourished. A 
stream, at the fall of the leaf, may float the decayed vegeta- 
tion out to any varying distance without being decomposed, 
and the water may quietly filter through a similar deposit, 
and leave the accumulation of several seasons' leaves, in a 
* Since this paper was read, it has been ascertained that the top of the tree 
was originally broken off at the period of the deposition of the shale, with 
which the interior is filled up, shewing very evidently that the vegetable tissues 
had been decomposed and washed away, leaving the bark to be converted into 
coal, and the centre a hollow cavity to be filled up by the material which was 
last deposited. The main strata which surrounds the tree is sandstone. 
