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 I20°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 plioccenus 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 distiicts. 
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 
