Gilboa - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 85

specifically, exchange of the gases oxygen
O 2 , and carbon dioxide CO 2 . Both plants
and animals exchange O 2 and CO 2 with
the environment across a semi-permeable
membrane but, because the O 2 and CO 2
molecules are both larger than the water
molecule, H 2 O, this membrane will leak,
resulting in a loss of water. To overcome
this problem, land plants have small holes,
stomata, in their waterproof cuticle, which
can be closed to prevent excessive water
loss. Animals, which might have used
external gills when living in water, have
lungs or tracheal systems (in insects,
spiders, and millipedes, for example) for
breathing air enclosed within the body,
and connected to the air by small holes
(called spiracles in insects).
Other adaptations which evolved during
terrestrialization include: stronger legs and
better balance to account for the loss of
buoyancy; sense organs which operate in a
medium with different optical and acoustic
properties (sound is used more for
communication on land); more careful
ionic balance, which is linked with the
reduced availability of water on land; and
the development of direct copulation
during mating (in water, gametes can

simply be discharged without the sexes
coming into physical contact). In spite of all
these problems, organisms swarmed onto
the land. It was, after all, an unexploited
ecological niche and there was, at least at
first, some escape from predators in the sea.

H ISTORY OF DISCOVERY OF
G ILBOA
The first settlement on the banks of
Schoharie Creek where it rushes through
gorges between the junctions of the
Manorkill and Plattekill tributaries was
established in 1764 by Matthew and Jacob
Dies. Where a river flows quickly, in a
gorge or over a waterfall, is an ideal spot
for the siting of a mill. As the number of
mills grew, the town of Gilboa was
established, presumably named after the
biblical Mt Gilboa in Palestine (Hernick,
1996: this topic gives a more detailed and
authoritative history of Gilboa fossil
studies). Fossil plant material is abundant
in the Devonian rocks of the area, and
the first district to be surveyed in the
geological survey of New York was the
Catskill Mountains ( 87 ). The publication
arising from the survey, by Mather
(1843), was the first to describe and

87

87 The Catskill
Mountains: a fall
view from near South
Mountain Quarry.