NOTES ON ESSEX GEOLOGY. 273
small section indeed has yielded far more species than those
that make up the present molluscan fauna of that sea. We
have here a fine example of what may be done by careful and
systematic examination of a pit that seems to be insignificant,
and this is a sort of work that is open to many who are pre-
vented from going far afield.
The latter part of this paper (pp. 719-738) is of more general
character and refers chiefly to Suffolk and Norfolk, in which
the Crags are much more largely developed than in Essex.
J. Lomas' Appendix deals with the inorganic constituents,
including the effect of percolating water, one case of which
at the base of the Beaumont Hall section, is noteworthy here,
The Crag rests on London Clay, "the sand and shells are black,
and so thick is the encrusting material that no part of the original
fragments can be seen." An analysis of the encrusting material
is given, from which it is seen to differ little from other material
in the pit, the notable points seeming to be the presence of a very
small amount of manganese and phosphorus, .21 per cent. of
each. The rarer constituents of the Beaumont Crag are zircon,
rutile, cyanite, andalusite, corundum, garnets, ilmenite,
leucoxene, tourmaline, biotite, muscovite, and felspars.
M. A. C. Hinton dealt with the "Pleistocene Deposits
of Ilford and Wanstead,"17 describing sections in the High
Terrace and in the Middle or Low Terrace, with figures of con-
torted beds at Ilford, from which place comes a list of 26
Vertebrata, chiefly Mammalia. He says that the high level
Drift of this district "gives strong evidence of the rigorous
nature of the climate during the earlier part of the Palaeolithic
period." But with the lower level Brickearth it is different,
and we have a rich fauna, with southern forms. I am rather
at a loss, however, when the author suggests that we should
"regard these deposits as belonging to one of the interglacial
periods since the formation of the great Chalky Boulder Clay,"
as I regard that as the latest truly glacial deposit in Essex.
The above-noted paper is followed by one on the "Pleistocene
non-marine Mollusca of Ilford," by A. S. Kennard and B. B.
Woodward.18 Besides the lists given, from examination by
the authors, there are nine recorded species of which they could
17 Proc. Geol. Assoc., Vol. xvi., pt. 6, pp. 271-281.
18 Ibid., pp. 282-286.