Geoscience Reference
In-Depth Information
Island in the Indian Ocean east of Madagascar, which was once
inhabited by the famous dodo bird—a large, flightless relative of
pigeons that was exterminated during the early days of European
exploration and colonization of the Indian Ocean. Anwar is one of
the world's foremost experts on this fascinating bird, which repre-
sents one of the most compelling stories in modern science about
humanity's role as an agent of extinction. Anwar served on our expe-
dition as a keen-eyed collector, as well as an excellent cook.
An intriguing fact was that the eggs were appearing within an
interval of the mudstone that was about two feet thick: some were
near the top of that interval, whereas others were near the bottom.
At this early stage of the excavation, we were not sure whether the
eggs were distributed in just one thick layer or whether there were
actually two layers of eggs closely packed on top of each other. Only
several days of patient excavation and Frankie's detailed mapping of
the eggs' distribution in the quarry could help us answer that ques-
tion.
On the other side of the field area, Lowell, Julia, and Alberto con-
tinued measuring the rock layers and collecting samples for magnetic
analysis. This work was rather tedious because, as mentioned earlier,
all one can do in the field is collect the samples. Analyses to deter-
mine whether the rocks had formed when the earth's magnetic field
was normal or reversed would have to wait until we returned to the
United States and worked on them in the laboratory. But in the
midst of this tedium, a punctuating moment of unexpected discov-
ery emerged.
We had discovered the first eggs and embryonic skin on our second
day in the field during the expedition in 1997. For some reason, our
second day in the field at Auca Mahuevo on our 1999 trip also turned
out to be magical. After a morning of measuring rock layers and col-
lecting magnetic samples, the geological trio headed down a ridge to
return to their vehicle to drive to the quarry where lunch was waiting.
On the way down the ridge, Alberto walked past some light beige frag-
ments of rock weathering out of the hillside. Bending down to pick up
one of the larger fragments, he could immediately see that these
weren't simply small rocks; they were fragments of fossil bone. After
calling Lowell and Julia over to examine the fossils, the crew began to
collect some of the larger chunks. Clearly, at least some of the frag-
