THE "RED HILLS" OF CANVEY ISLAND. 143
the Essex Red-hills examined by the Exploration Committee
appears, from the analysis made by their chemist, Mr. J. H. B.
Jenkins, to contain an excess of silica over that corresponding to
what may be termed the clay content proper—which I take to
correspond to 18.3% alumina (AI2O3)—sufficient to indicate that
it is a sandy loam corresponding in composition to that found in
the lower working levels at Canvey Island, a material in every
respect suitable for the manufacture of the briquetage found
on the neighbouring sites. Thus—
RESULTS OF ANALYSIS.
Clay from side of Red-hill. SandyLoam, Canvey
(Mr. Jenkins' results, restated) (at 4ft. depth)
"Sand " 28 27+
"Clay proper ". . 72 73
100 100
The briquetage recovered from the cindery burnt earth, and
the burnt earth itself were found by Mr. Jenkins to contain
Alumina and Silica corresponding to material of composition
(results restated):—
Briquetage. Red Burnt Earth.
" Sand " .. 20 31
" Clay proper ".. So 69
100 100
Mr. Jenkins, summarising the results of his analyses, says:—
The essential similarity in chemical nature of the briquetage,
"red earth, and clays is, however, evident, and we may conclude
"that, if the material constituting the Red-hill has been trans-
"ported to its present position from some other place of origin,
"at any rate the clay used in its production was of the same
"character as that found in the place to which the material has
"been transported."
Analysis indicates, therefore, that the sandy loam, red burnt
earth, and briquetage are closely related in respect of their
content of sand and clay. Experiment shows that if a sample
of the loam is half-baked by contact with fire a soil closely resem-
bling burnt earth is obtained. Whilst, if the firing be continued
4 Recoverable by washing process.