Gilboa - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 90

preparation. They took slides bearing the
animal pieces to various experts on fossil
arthropods, and the importance of the
find was immediately recognized by W. D.
Ian Rolfe, then of the Hunterian Museum,
Glasgow, Scotland. Rolfe realized that,
with so many different animal taxa
present, he needed expert advice from
workers on mites, other arachnids, and
myriapods to do justice to this material.
He showed pictures to William A. Shear, of
Hampden-Sydney College, Virginia, an
expert not only on modern arachnids but
on myriapods as well. Shear and Rolfe
became excited about the find, reported it
in the journal Science with Bonamo,
Grierson, and other colleagues (Shear et
al . 1984), and then set to work describing
the fauna group by group.
Following the discovery of the
exceptional early terrestrial fauna at
Brown Mountain, a number of other
sites in the Catskills were searched for
similar animal remains. So far, one
other site has proved fruitful: a shale
quarry in slightly younger beds near
Conesville, east of Gilboa, referred to as
South Mountain. The Gilboa area
localities are of international importance
because there are so few places in the
world where a nearly complete early
terrestrial ecosystem has been preserved
and can be studied. Gilboa gives a rare
insight into what the life on land was like
shortly after it first emerged from the sea.
Important though the Brown Mountain
site is, it is now buried under tons of
concrete of the Blenheim-Gilboa
Reservoir. Bonamo and Grierson rescued
as much of the lens of rock as they could,
which is now stored at Binghamton, and
where it was worked on for several years
after the loss of the site.

Mountain, and South Mountain. As
mentioned in the last section, the
preservation of fossils at the Brown
Mountain locality is rather unusual in that
the organic matter is not oxidized or
carbonized but retains its complexity. It is
not the original plant and animal cuticles
that are preserved, however, but randomly
polymerized complex organic molecules.
Hence, the fragments retain a brown
coloration, some transparency and
flexibility, despite being flattened in the
fine mudstone. This means they show
incredible details under the light
microscope but are not three-dimensional
except in occasional cases where iron
pyrite has infilled spaces and cells. For
paleobotanists, the variety of preser vational
types, combined with a range of
techniques - light microscopy, scanning
electron microscopy (SEM), and chemical
preparation techniques - provided them
with exceptional views of early land flora.
For the paleozoologists, light microscopy,
rather than SEM, proved to be the ideal
method to view the fauna.
At Riverside Quarry and other
localities that yield stumps (Goldring,
1924, 1927; Driese et al ., 1997) the plant
foliage is carbonized, but the stumps are
sandstone casts. The stumps are
preserved in life position, seated on a
paleosol (fossil soil) represented by a
15-60 cm (6-24 in) thick claystone, and
surrounded by coarse, cross-bedded
sandstone. Adjacent to the stumps,
Goldring found loose trunks up to 4 m
(>12 ft) in length. In one small area, 18
stumps were found, 1-2 m (3-6.5 ft)
apart. The study by Driese et al . (1997)
showed that the roots radiating up to 3 m
(9 ft) from the stumps into the paleosol
were shallow, and the gley nature of
the paleosol indicated waterlogged con-
ditions. We can envisage a swamp forest
of Eospermatopteris trees, similar to the
Swamp Cypress ( Taxodium ) forests of the
south-eastern seaboard states today,
which became inundated by breaches of
the levee or coastal barrier, bringing in
cross-bedded sands. The inundation

S TRATIGRAPHIC SETTING AND
TAPHONOMY OF G ILBOA
It will be clear from the foregoing that we
are actually dealing with a number of
localities in the area around Gilboa, at
least three of which are particularly
important: Riverside Quarry, Brown