146 THE ESSEX NATURALIST
When he received the Prestwich Medal of the Geological Society of
London in 1939, the President said that an interesting feature of
Warren's work was his carrying the methods of Lyell into the field of
archaeology: that is to say he studied present-day analogues in order
to throw light on prehistory. For example, his studies of the primitive
huts of the charcoal burners of Epping Forest were used to elucidate
observations on prehistoric hut-circles. Again, his observations on the
fracturing of flint now occurring through movements in the Bull-head
Bed below the Thanet Sand at Grays served to confirm his doubts on
the human origin of eoliths.
Examining the submerged land-surface on the Essex coast, which he
named the Lyonesse Surface, he discovered the first record of the
grooved pottery closely related to that of the Dutch megalith builders.
He also made observations on the prehistory of the submerged land-
surface of the Lincolnshire coast. Indeed, he carried his archaelogocial
enquiries much further afield, notably in the Isle of Wight. Cornwall.
France and North Wales. Returning in 1919 to the geological stamping
ground of his youth he discovered the first Neolithic axe-factory known
in Britain outside the flint country: Graig Lwyd on the northern slopes
of Penmaenmawr, where he was able to collect enough material to show
all the stages of manufacture. Finished axes of the Graig Lwyd green-
stone (augite granophyre), forming Group VII in the nomenclature of
the Committee on the Petrological Identification of Stone Axes, have
been traced as far south as Lee-on-Solent, and as far east as Cambridge.
Warren's industry combined with his natural gift for discovery and
his unusual skill as a collector enabled him to build up a remarkable
private museum of his finds. In the Essex Naturalist of 1910. we read:
"Mr. Warren has been accustomed to throw his museum open to
public inspection on certain afternoons and evenings, and to give
short expositions and explanations for the information of his visitors.
His generous and enlightened action in this, one of the best forms
of popular education has, we understand, been highly appreciated in
the district."
He was always ready to let students examine the extensive collections
stacked with great ingenuity in his house—"Sherwood" in Forest View
Road. Loughton. Part of his collection, including all the Pleistocene
mammalia, was acquired by the British Museum (Natural History) in
1936. After this bulky transfer, the Warrens moved into a new and
smaller "Sherwood" built on ground adjoining the old. His collections,
still large, were stacked with even greater ingenuity in the new abode,
where his friends in prehistory were always sure of a welcome. He
bequeathed all the remaining specimens to the British Museum.
Warren's married life was a happy one. He married Agnes Mary
Rainbow in 1903, at about the same time leaving the family business
and devoting his life almost entirely to Pleistocene geology and archae-
ology. His capable wife, who became Commandant of the 36th division
of the Red Cross at Loughton in 1914-18, was keenly interested in his
work, and therefore a cheerful helpmate throughout their life together.
She died in 1937. On field trips they were always accompanied by the