Introduction
Near
Gilboa, New York, Devonian aged limestones, shales, and sandstones
provide windows into several different habitats. The first
appearance of trees and a forest are found in the fossils
of Gilboa (385 million years ago). Stumps with roots stretching
out into a paleosol (fossil soil) have been preserved as
sandstone casts at a site known as Riverside Quarry. The
stumps were given the name Eospermatopteris and
are now known to be a cladoxylopsid. Cladoxylopsids are thought
to be ancestors of ferns and horsetails. Recently, two Gilboa
trees with trunk and branching crowns were found lying prostrate.
The trunk of the trees was identified as a cladoxylopsid
of the genus Wattieza (Stein et al, 2007, pp 904-907).
Illustrations combining Wattieza with Eospermatopteris give
paleontologist an idea of what this Gilboa tree looked like
in real life. Carbonized foliage at Riverside Quarry preserves
arboresent and herbaceous lycopods, such as Lepidosigillaria and Leclercqia.
Progymnosperms like Aneurophyton can also be found.
In the Devonian, Riverside Quarry was a swampy forest near
a coastline. A second location near Gilboa, known as Brown
Mountain, is a lagerstatten, which preserves important animal
fossils in what was once a tangled mass of Leclercqia (a
herbaceous lycopod) and mud, which was located in a deltaic
environment. Fossil foliage at Brown Mountain includes lycopods,
progymnosperms, and cladoxylopsids. Animals preserved in
the tangled Leclercqia mud mass at Brown Mountain
include: eurypterids, scorpions, trigonotarbids (spider-like
organisms), the first known spider, the first known pseudoscorpions,
millipedes, and centipedes. A third site, called South Mountain,
represents a deltaic environment like that found at Brown
Mountain. Fossil foliage at South Mountain is a mix of lycopods,
progymnosperms, and cladoxylopsids. Two types of fish are
found at South Mountain, placoderms and acanthodians. Gilboa,
like other Devonian aged fossil ecosystems, represents a
primitive trophic structure that lacks herbivory; only predator-detritivore
food chains existed at this time (Nudds & Selden, 2008,
pp. 95-113). |
Nudds
J.R. & Selden P.A. (2008). Fossil Ecosystems of North
America: A Guide to the Sites and Their Extraordinary Biotas.
Chicago: The University of Chicago Press.
Stein,
W.E., Mannonlini, F, VanAller Hernick, L., Landing, E. & Berry,
C.M. (2007). Giant cladoxylpsid trees resolve the enigma
of the Earth's earliest forest stumps at Gilboa. Nature,
vol 446: pp. 904-907. |