136 REPORT ON THE LICHENS OF EPPING FOREST.
I have been unable to get any help as to the age of
the deposit in which these bones were found from either
the Map or Memoir of the Geological Survey, and a reference to
my friend, Mr. W. H. Dalton, who was largely responsible for
this work, has failed to satisfy my desires. He tells me that he
knows of no deposit in the neighbourhood later than the
Boulder Clay, which could be termed prehistoric. We can
only agree, therefore, with Dr. Irving in saying that the age of
the Bishop's Stortford horse is "dubious."
REPORT ON THE LICHENS OF EPPING
FOREST (FIRST PAPER).
By ROBERT PAULSON, F.R.M.S. and PERCY G. THOMPSON.
[Read 5th March 1910.]
IN a paper by the late Rev. J. M. Crombie, read to the Club
on 28th April 1883,1 the writer says:—"It will be
interesting to the lichenist of the future, some 50 or 100 years
hence, to compare the above list with those that the Forest may
then present." He adduces, as the chief causes affecting the
diminution of the Lichen Flora, (1) the destruction of the older
trees, (2) want of due access of light and moisture to the existing
trees, and (3) the increase and extension of villages in the neigh-
bourhood.
It may be well, after an interval of 27 years only, to inquire
how far and to what extent the above causes have operated.
The first has only done so to a limited extent; for there has
not been that wholesale destruction of the older trees which
Crombie anticipated. Consequently, as many of the species in
Forster's Herbarium had already in Crombie's time become
extinct by reason of wholesale destruction, the rate of diminution
within the last quarter of a century has been very much slower.
There is reason to believe, indeed, that there has been a slight
recovery, if not of species reappearing, at least of species that
were barren becoming fruitful again.
The second cause does not, perhaps, operate to the extent it
did 27 years ago. For some time past, a certain amount of
judicious felling has let in light and moisture, with beneficial
effect. Since the abolition of the tree-lopping, the lichens of the
1 "The Lichen Flora of Epping Forest, and the Causes Affecting its Recent Diminu-
tion," Transactions E.F.C., iv., pp. 54-75 (1885).