an “island” of Devonian Gondwana — a 
portion of Andean South America that 
had somehow become detached and in- 
corporated as an exotic chunk into 
what later became Costa Rica. A radi- 
cally new view of shifting fragments of 
continental plates colliding to form 
portions of Central America started to 
take shape in my mind. It was too late 
to stop the Natural History presses, but 
I began to envision a quick report to 
Science or some other prestigious 
“what’s the latest development in sci- 
ence” journal. 
But there was a small fly in the oint- 
ment. Paguaga said he got the trilobite 
from a small boy who had brought it to 
school. The boy had found it on a local 
roadside. If we were to tell the world of 
an exotic Devonian “island,” we had to 
be able to point to a mass of rock and 
say, “There it is.” Another specimen 
Paguaga brought with him seemed 
promising: a chunk of brown siltstone 
about the size of a silver dollar. It had 
shell fragments that looked the right 
age on one side, and a gorgeous fossil, 
which I took to be a previously unre- 
corded variety of phyllocarid, a type of 
crustacean especially well known in 
Devonian rocks. About an inch long, 
the symmetrical structure was elabo- 
rately sculptured with a variety of 
bumps and furrows reminiscent of, al- 
though a bit more complicated than, 
the carapaces of known phyllocarids. 
We seemed to be in good shape, but Pa- 
guaga understood the necessity for 
ironclad evidence that the trilobite was 
indeed a native of Esparza. 
Shortly after his return home, Pa- 
guaga went to work, and I was soon 
bombarded with packages of Costa Ri- 
can fossils. Concentrating on the out- 
crop that had produced the crustacean, 
he found more than fifty complete fos- 
sils and shipped them all to New York. 
To my chagrin, all proved to be clams 
and snails no older than twenty or thir- 
ty million years — very much the sort of 
thing one was supposed to find in Costa 
Rica. 
With my doubts deepening, I re- 
trieved the “crustacean” from the col- 
lection of Costa Rican fossils, stared at 
it hard, and realized it was not a phyllo- 
carid after all. It was (and I am no bota- 
nist) apparently some sort of nut or 
seed pod. Groaning, I realized my en- 
thusiasm had carried me away. I had 
fantasized a Tertiary fruit into a De- 
vonian crustacean! All of a sudden I 
was quite glad I hadn’t batted out a 
note to Science trumpeting our wonder- 
ful discovery. 
The real story of the Esparza trilo- 
bite is not exactly fraught with scientif- 
ic significance. It turned out my first 
suspicion about the origin of the fossil 
was right. An American, leaving La 
Paz, Bolivia, to live in Costa Rica, 
bought the trilobite from an “old Indi- 
an" as a souvenir. (I hear that these tri- 
lobites have been for sale all over La 
Paz in recent years.) He had a minor 
car accident on a Costa Rican road one 
day, and the trilobite was lost — only to 
be found by the little boy. All the details 
were uncovered by Paguaga — a dogged 
truth seeker if ever there was one — who 
advertised in the papers and tracked 
down the American, still living in Costa 
Rica. Of the thousands of Andean fos- 
sils in my office, none has taken a more 
circuitous route from the mountains of 
Bolivia to our labs in New York. 
The whole episode, as absurd as it 
may seem, really does show how sci- 
ence works. The misplaced trilobite 
challenged several longstanding no- 
tions I had confidently recounted in my 
article for Natural History. Either the 
ideas or the trilobite had to give. 
In the end, I was sorry not to have 
been a party to a real discovery. It 
would have been nice to have had the 
chance to exclaim “Eureka!” the way 
scientists are popularly supposed to do. 
You know the image. After years of te- 
dious measurement, a new generaliza- 
tion on the properties of matter 
suddenly dawns on the patient physi- 
cist; after much careful planning, the 
pith-helmeted coot in khaki shorts bags 
a “hitherto-unknown-to-science” but- 
terfly in the depths of Amazonia. Eu- 
reka! But, alas, eurekas are damn hard 
to come by. The true stuff of science re- 
mains the sure and steady checking of 
ideas against worldly realities. 
Niles Eldredge is a curator in the De- 
partment of Invertebrates at the Ameri- 
can Museum of Natural History. 
26 
