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exposed in huge, wave-cut sea cliffs. Ward's favorite outcrops were
near the town of Zumaya, where a strong iridium anomaly was
found in the same kind of thin clay layer as at Gubbio. In 1983, not
long after the appearance of the Alvarez theory, Ward reviewed the
life and death of these fascinating creatures in an article in
Scientific
American.
6
Because the highest (youngest) ammonite he could find
occurred some 10 m below the K-T boundary—equivalent to tens
of thousands of years before the impact—Ward concluded that the
Alvarezes were wrong: "The fossil record suggests . . . that the ex-
tinction of the ammonites was a consequence not of this catastrophe
but of sweeping changes in the late Cretaceous marine ecosystem . . .
studies ... at Zumaya suggest they became extinct long before the
proposed impact of the meteoritic body."
7
At the end of his article,
however, Ward added a crucial caveat: "This evidence is negative
and could be overturned by the finding of a single new ammonite
specimen."
8
Ward's reference to negative evidence was meant to emphasize
that the absence of evidence is not evidence of absence. Failure to
find a fossil species at a given horizon near its upper limit does not
prove that the organism had already gone extinct at that level, as
Ward understood—maybe a more diligent search would turn it up.
The only way to make progress against the Signor-Lipps effect is to
return and search again. Ward returned to Zumaya to do exactly
that. "Finally, on a rainy day," he writes, "I found a fragment of an
ammonite within inches of the clay layer marking the boundary."
9
Thus encouraged (and perhaps influenced by the appearance on
the Zumaya beach first of armed Spanish soldiers and later of dis-
gruntled Basques, each asking what he was doing to their rocks),
Ward began to enlarge his collecting areas to include other sites
along the Bay of Biscay where the K-T boundary is exposed. With-
out the impetus of the Alvarez theory, Ward would not have gone to
this extra trouble. What would have been the incentive to spend
more of his life on these same cliff faces? His redoubled effort paid
off. Within the first hour of collecting near the French town of Hen-
daye, just around the corner from Spain, he found abundant
ammonites in the last meter of Cretaceous rock. In papers given at
the second Snowbird conference in 1988, Ward reported that "col-
lecting... east and west of the Zumaya section ultimately showed
that ammonites are relatively common in the last meter of the Cre-
taceous sediment."
1
0
He thought that their scarcity at Zumaya had
stemmed "from some aspect of ammonite ecology, rather than col-
lection failure or preservation effects."
1
1
For now vanished reasons,
the ammonites had migrated away from Zumaya, but had not gone
