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forts yielded fascinating results: As the septa in the virtual ammonites be-
came more complex, the stresses applied to them became more catastrophic.
Our first runs examined simple cup-shaped septa and then septa with folds
and kinks that looked vety much like the septa of early ammonites. The sim-
ple cap-shaped septa proved far more resistant to stress; this was the insight
that had led Tom, on our first meeting, to suggest that ammonite septa had
not evolved primarily because they afforded sttength against implosion. This
was clearly not the scenario that ammonite paleontologists envisioned. The
evolution of mote complex septa was supposed to make the shells stronger,
not weaker. Perhaps it was the methodology? Were we forgetting something?
We went back to the drawing board. Bruce Saunders and I were sent to our
collections, where we sectioned ammonites and made exacting measure-
ments of the thickness of wall and septa, for we needed to enter these values
into the computation models if any sort of relationship with reality was to be
achieved. In the process we learned much about the average thickness of real
ammonites, and all this information was fed into the models.
Weeks turned to months, and months to years, as Tom and his grad stu-
dent Btian Helmuth, who had joined the project, produced ever more elab-
orate ammonites. Computational time soared. We were now running ter-
abits of computations, and eventually eleven Silicon Graphics machines
were running simultaneously, days at a time, for each run required an hour
and yielded just a single data point. Over time, the simulations wete made
not just on septa but on shells with septa within; the results as they flashed
up on the screen were hauntingly beautiful. The images showed the distribu-
tion of stresses as colors, and the ammonites would light up as spectacles of
sparkling reds and yellows, blues and greens dancing across septal junctions
and shell wall. By late 1996 an entite school of ammonites lived in the base-
ment of Kincaid Hall, populating the bowels of the building rather than the
ocean deeps. The machines now ran simultaneously, and Brian Helmuth ran
between them for all the hours of many days, plucking a new number from
each laborious, hour-long computation. As T.
rexes
lived and died in the
California studios making
Jurassic Park,
the brethren of these powerful ma-
chines raised ammonites from another grave in Seattle.
