216 THE ESSEX NATURALIST.
History" (1903) shows that the moth has been found at Shoeburyness 
and duly recorded by Harwood under its synonym of G. auroguttella.—
Editor.
A Severe Ordeal.—A river-crab (Potamonedule), f. from Algiers,
which has been in the Stratford Museum since May, 1926, was frozen
solidly into the ice at the bottom of its tank (in an inert condition), for
two whole days during the severe frost of February, 1929. It had to be
thawed out by repeated additions of warm water, when it was found to be.
alive and unharmed.
Its companion in the icy water, a Spanish Terrapin (Clemmys leprosa),
from the same district, also survived its presumably unique experience,
but it was not frozen in as was the river-crab.—Percy Thompson.
Agatized Wood from Arizona.—Several fine specimens of silicified
timber from the so called "petrified forests" of Arizona, U.S.A., have
recently been presented to the Stratford Museum. Trunks of large coni-
ferous trees, some up to 200 feet in length and from 7 to 10 feet in diameter,
cover some eight square miles in Arizona, New Mexico and Utah, they are
probably of Triassic age. The term "forest" is incorrect, seeing that
none of the trunks is erect in the position of growth ; all is drift-timber,
transported by water from its original place of growth before fossilisation.—
Percy Thompson.