278 NOTES ON ESSEX GEOLOGY.
1908.
J. H. B. Jenkins gave us a rather rare thing, a chemical
analysis of London Clay.31 The sample was from a boring at
East Ham, which, on being heated to 120°C. lost 20.7 per cent.
of its weight, with a further loss of 6.3 per cent. on ignition.
The residue consisted chiefly of silica, 67.9 per cent., with
alumina 18.3
M. A. C. Hinton did us a service in discussing fossil monkeys,
with reference to a specimen said to come from the Grays brick-
earth.3'2 It had been doubted whether the specimen came
from Grays, and it had been suggested that Macacus ought not
to occur at Grays. But the author, discussing these questions,
says that the Grays brickearth alone, amongst the Middle
Terrace deposits, yields a. southern fauna, and that for this
reason and because the "mineral condition of the fragmentary
jaw agrees with the other fossil bones from Grays," he regards
"the only known specimen of Macacus pliocaenus as a genuine
Grays fossil." So Essex keeps its monkey.
1909.
In this year the Geologists' Association celebrated its Jubilee
in a remarkable way, said celebration for the most part ex-
tending over into the following year. The Jubilee volume
Geology in the Field consists of a set of essays, mainly describing
the geology of various counties or districts, as seen during various
excursions of the Association ; but a good deal of other geologic
matter was wisely included. Twenty-nine authors took part
in the work, all of them of course well up in their special districts.
Essex is described by our old friend T. V. Holmes and his
paper consists mostly (pp. 58-85) of a description of excursions
that had been made to the following districts, many of which
had been often visited : Grays Thurrock, Upminster, Ilford,
Brentwood, Laindon Hills, Ingatestone, Rayleigh Hills, Chelms-
ford, Danbury, Kelvedon, Walthamstow, and Epping Forest.
It will be seen therefore that it mainly deals with the southern
and central parts of the county, the northern parts being alluded
to only in the general account (pp. 51-57).
The veteran Norwich geologist, F. W. Harmer, contributed
31 Geol. Mag., dec. v., Vol. v., pp. 265, 266.
32 Ibid., pp. 442-444.