The Bertie Waterlime - Fossil Ecosystems of North America: A Guide to the Sites and their Extraordinary Biotas - page 81

C OMPARISON OF THE B ERTIE
W ATERLIME WITH OTHER L OWER
P ALEOZOIC BIOTAS
Klussendorf (1994) compared the Bertie
Waterlimes with other, similar Silurian
biotas in the north-eastern states using
cluster analysis and found that it grouped
with other eurypterid-phyllocarid
dominated localities such as Kokomo,
Indiana. The Eurypterus Beds of the
Silurian sequence in the Baltic region of
Europe are remarkably similar in many
ways to the Bertie Waterlimes. These are
beautifully exposed on the Estonian
island of Saaremaa and the Swedish island
of Gotland. The beds in Gotland and
Estonia appear to be of the same age
(latest Wenlock) and differ in that the
preservation of the eurypterids is rather
better in the Gotland dolostones than
those of Saaremaa (Selden, 1981). The
Bertie Waterlimes are younger (Prídolí)
than the Baltic sequence.
Today, because of the high level of
plate tectonic activity which includes
raised mid-ocean ridges, sea levels are
higher than they were in the Silurian. The
seas over the continental shelves now are
deep, but during late Silurian times, vast,

shallow seas occurred on the continental
shelves, known as epicontinental seas.
Both contain abundant specimens of
Eurypterus and also pterygotid and other
eurypterid species. In both cases the
eurypterid remains are fragmentary and
seem mostly to be molts. Both Bertie and
Baltic dolostones also contain horseshoe
crabs, lingulid and other brachiopods,
orthocone nautiloids, gastropods and
phyllocarid crustaceans. Both the Baltic
region of Europe and New York lay
together on the edge of the same
continental land mass, Laurentia, so when
we compare the two Lagerstätten, we are
really comparing very similar ecosystems
separated in space and time. The species
of Eurypterus, Pseudoniscus etc. are
different, just as E. remipes differs from
E. lacustris because some morphological
evolution occurred during the time
between deposition of the Fiddlers Green
and the Williamsville Waterlimes. The
amount of evolution which occurred in
the time between deposition of the Baltic
beds and the Bertie was presumably
rather more and so the species of
Eurypterus , for example, are clearly
separable.

F URTHER R EADING
Andrews, H. E., Brower, J. C., Gould, S. J.
and Reyment, R. A. 1974. Growth and
variation in Eurypterus remipes
DeKay. Bulletin of the Geological
Institution of University of Uppsala:
New Series 4 6 , 81-114.
Banks, H. P. 1973. Occurrence of
Cooksonia , the oldest vascular land
plant macrofossil, in the Upper Silurian
of New York State. Journal of the
Indian Botanical Society 50A , 227-235.
Braddy, S. J. and Dunlop, J. A. 1997. The
functional morphology of mating in
the Silurian eurypterid,
Baltoeurypterus tetragonophthalmus
(Fischer, 1839). Zoological Journal of
the Linnean Society 121 , 435-461.

Budd, G. E. 1999. A nektaspid arthropod
from the early Cambrian Sirius Passet
fauna, with a description of
retrodeformation based on functional
morphology. Palaeontology 42 ,
99-122.
Caron, J-B., Rudkin, D. M. and
Milliken, S. 2004. A new late Silurian
(Pridolian) naraoiid (Euarthropoda:
Nektaspida) from the Bertie
Formation of southern Ontario,
Canada - delayed fallout from the
Cambrian Explosion. Journal of
Paleontology 78 , 1138-1145.
Chapman, E. J. 1864. A Popular and
Practical Exposition of the Minerals
and Geology of Canada . Toronto.