Origin: A Genetic History of the Americas

But Halligan told me that “people were pretty dismissive” about the
discovery. “There’s a long tradition in archaeology of inviting experts out to
see your site while you excavate it,” she explained. “If you find something
really controversial, you have people come out and look at it. But unlike
other sites, because this one is underwater, most archaeologists couldn’t
visit it to assess it themselves” (1).
Many of Halligan’s methods are similar to those of her colleagues who
excavate aboveground—she excavates a single geological layer at a time,
carefully scraping the earth away with a trowel, documenting details of the
stratigraphy and artifacts by hand and camera. But in her case, she also
happens to be doing this underwater, in scuba gear, which means she can
only work for short periods of time before she switches places with a
colleague for safety. The sediment she trowels away from each layer isn’t
collected into a dustpan for screening but sucked by a water dredge through
a large hose. “It looks much like your average dryer hose, except reinforced
so it’s not so bendy,” Halligan explained. The troweled sediment is
deposited onto a screen that floats on the surface of the water, where other