144 THE ESSEX NATURALIST
he spent a considerable time in North Wales, and lacking any personal
guidance or help, he gained greatly, he said, from his determination to
puzzle out for himself the geology of that country, with the official
Survey memoir by A. C. Ramsey as his only guide. At the age of
twenty-five he became a member of the Geologists' Association. In the
same year he published his first geological paper. It dealt with rubble-
drift at Portslade in Sussex. He soon displayed that independence of
outlook for which he became so renowned, and at the age of twenty-
eight he exhibited, at a meeting of the Geologists' Association, specimens
which showed that the so-called Eoliths could be of natural origin.
As a result of prolonged field observations, and supplemented by
ingenious experiments in his workshop, Warren showed how natural
agencies such as soil-creep, sub-soil and sub-glacial pressures, can
fracture flint in ways simulating human work to a remarkable extent.
These investigations led him to adopt a cautious and eventually ex-
tremely critical attitude not only towards the classical eoliths but towards
the chipped flints regarded by many as "Pre-Palaeolithic artifacts" in
and below the Crag deposits of East Anglia. He was one of the leading
figures in that acrimonious controversy which raged over the Sub-Crag
flakings during the first quarter of the present century. Whether it
helped or not in this connection, the fact remains that he had a great
sense of humour, and knowing of the many indications that the Sub-
Crag surface was submarine, he would say with a wicked twinkle in
his eyes, "I call these flakings the work of mermaids," the kind of
comment invariably followed by his characteristic, mischievous chuckles.
With F. N. Haward as almost his only ally, Warren fought for years
against the over-ready acceptance of these flints as artifacts, and it was
immensely gratifying to him to see the tide of opinion gradually turning
in the direction where he had led. In 1939, Professor Alfred Barnes.
for years one of the strongest believers in the "Pre-Palaeolithic indus-
tries", changed his opinion through discovering by statistical analysis
that the Crag flaking was of the high-angled type characteristic of the
work of nature. Warren showed, moreover, that nearly 50 per cent
of the flints in the Sub-Crag Stone Bed are flaked to some extent, and
as the deposit covers several hundred square miles, his logic was really
irrefutable when he said that a widespread natural cause was probably-
responsible. The striations and bruisings that many of the flints show-
are consistent with his idea that the chief cause of the flaking was the
grounding of local pack-ice which jammed together patches of flint
strewn on the floor of the shallow Crag sea during Early Glacial times.
Warren will also be remembered for his extraordinary flair for dis-
covery. He was amused to relate that the first worked flint he ever
found in boyhood, was on Edinburgh Castle Rock; but it was not pre-
historic as he fondly imagined at the time, but a gun-flint! In the light
of his many successes as a collector in the course of a long life he once
gave this advice to encourage beginners: "What discoveries I have had
the good fortune to make, have come through persistently searching in
neglected and often unlikely places, without being discouraged by draw-
ing many blanks".