decay produced another mass of vegetable matter fit to form coal. This
again was let down below the water, more shales and sandstones were
deposited on the top, and this process went on over and over again till
the whole mass of our present coal measures was formed. You will now see
how it is that trees are so seldom found in an upright position in the
coal beds. As the land went down, they would in very many cases be
toppled over by the water as it flowed against them, or their base would
be rotted, and they would then either fall or be blown over; that is the
reason why in most cases they are found lying flat on the roof of the
coal bed. But in a few cases, when the depression was very gentle and
gradual, the trees were not overthrown, and the shales and sandstones
accumulated round them and preserved them in the position in which they
grew.

I do not know that I can point out to you anything nowadays that exactly
resembles the state of things that must have gone on during the times
these coal measures were being formed; but there are a great many cases
strikingly analogous to them. I shall not attempt to describe them to
you, but may just mention the mangrove swamps that very often fringe the
coasts in the tropics, and the cypress swamps of the Mississippi, which
are so well described by Sir Charles Lyell in his recent works; also
the great Dismal Swamp of Virginia, which appears to me to furnish the
nearest analogue to the state of things that existed during coal measure
times.

Having explained the way in which coal measures have been formed, we
will now take a brief sketch of its uses and products. The year 1259 is
memorable in the annals of coal mining. Hitherto the mineral had not
been raised by authority, but in that year Henry III. granted a charter
to the freemen of Newcastle-on-Tyne for liberty to dig coal, and a