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W. D. Boyce
Provincial Paleontologist
Newfoundland and
Labrador Department of Mines and Energy
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Introduction
The province of Newfoundland and Labrador is world famous for
its fossils and has long been favored by collectors and researchers.
In eastern Newfoundland, trilobites and acritarchs (plant
microfossils) are the most common fossils. They occur in
marine-deposited shales and slates of Cambrian and Ordovician age on
the Avalon Peninsula (including Bell Island), the Bonavista Peninsula
(including Random Island) and the Burin Peninsula. Accompanying the
trilobites may be less abundant inarticulate brachiopods, graptolites
and hyolithids. Bell Island is world famous for its trace fossils
(tracks, trails and burrows produced by trilobites and soft bodied
animals).
In central Newfoundland, bivalves, articulate brachiopods,
bryozoa, cephalopods, conodont microfossils, corals, crinoids,
gastropods, graptolites, ostracodes and trilobites are variably found
in marine-deposited conglomerate, limestone, sandstone, shale and
slate of Ordovician and Silurian age. Fossils are particularly common
on New World Island.
Western Newfoundland and southeastern Labrador have the
greatest variety of fossils. Marine fossils occur in conglomerate,
limestone and marble, sandstone, shale and slate of Cambrian,
Ordovician, Silurian, Devonian and Carboniferous age; they variably
include acritarch microfossils, archaeocyathids, bivalves, articulate
and inarticulate brachiopods, bryozoa, cephalopods, chitinozoan and
conodont microfossils, conularids, corals, crinoids, gastropods,
graptolites, hyolithids, monoplacophorans, ostracodes, rostroconchs,
sponges, stromatolites (and thrombolites) and trilobites. These occur
on the Port au Port Peninsula and the Great Northern Peninsula.
In the Deer Lake basin and the Anguille Mountains,
terrestrial- and freshwater lake-deposited sandstone and shale locally
contain plant and fish remains. Cretaceous age insect and plant fossils
have been recovered from the Redmond iron ore deposit of the Knob Lake
District of western Labrador; unfortunately, no dinoaur remains were
found. During the offshore oil exploration on the Grand Banks, however,
dinosaur bones were encountered by the drills.
Biostratigraphic Uses of Fossils
Paleontologists and biostratigraphers (geologists who study fossils)
have long recognized that fossil assemblages occur in a certain order
in the sedimentary rock record. These assemblages have been used to
define biostratigraphic zones. Zones are typically named for their most
common and/or distinctive species. The base of each zone is defined by
the first appearance of its characteristic species. The top of a zone
is automatically defined by the base of the next zone. Two or more
zones grouped together form a geologic stage. Stages are linked to form
a geologic series. Series combine to form a geologic system or period.
The zone is therefore the fundamental building block of the geological
time scale. Consequently, discussions of geological history which
ignore the timing provided by fossils and fossil zones, do so at their
own peril.
Trilobites, graptolites, and brachiopods (macrofossils) and conodonts
(microfossils) are particularly useful for dating rocks of the
Cambrian, Ordovician and Silurian systems. They had a high rate of
evolution during the Cambrian, Ordovician and Silurian periods. The
composition of the faunas changed many times so that many zones are
recognized. At the same time, the above organisms were abundant and
widespread. This has made it possible to correlate faunas of the same
age over great distances.
Faunal Provincialism - An Example
The Cambrian trilobite faunas of eastern Newfoundland contrast sharply
with those of western Newfoundland (and most of North America). This is
because the two areas were originally in different climatic zones on
opposite sides of an ancient ocean called Iapetus. While western
Newfoundland (and most of North America) was located at or near the
equator in relatively warm, shallow water, eastern Newfoundland was
located in higher (temperate to polar) latitudes and covered by
relatively cool, deep water. Continental drift later brought the two
areas together.
The Cambrian faunas of eastern Newfoundland (also New Brunswick, Nova
Scotia, Massachusetts) in fact have more in common with those of
Norway, Sweden, England, Wales, France, Spain, Germany and the Czech
Republic (Bohemia). These faunas collectively belong to what is called
the Acado-Baltic faunal province. Eastern Newfoundland is one of the
best places in the world to examine Acado-Baltic trilobites.
Collecting Fossils
When looking for fossils, it important to remember that complete
specimens are rarely found. While complete specimens are better for
scientific description in paleontological studies, even a poorly
preserved fossil fragment is often enough for field identification and
dating of rocks.
Fossils can be found by picking through weathered rubble along cliffs,
beaches, streams, quarries, road and railway cuts and rock outcrops.
Finding them in place, however, requires a careful layer-by-layer
examination of the enclosing sedimentary rocks with a hammer and
chisel.
Many Newfoundland fossils are quite small and easily overlooked. It is
wise, therefore, to have a magnifying glass or a hand lens for checking
favorable rock types.
Good eye protection is essential, preferably in the form of safety
glasses. A good geological hammer with either a chisel or a point made
of well tempered, shatter-free metal is advisable. A stone chisel and
small sledge hammer are also useful. Broken fossil specimens can be
repaired in the field with nontoxic white glues such as Lepage Bond
Fast. Modelling clay, liquid latex (such as Lewiscraft rubbertex
compound or ETI Mold Builder) or plaster can be used to
obtain a replica of an otherwise nonretrievable specimen. Fossils
which can't be collected may also be photographed or sketched. After
collection, all specimens ought to be securely wrapped in tissue or
newspaper and then placed in a well labelled bag to prevent damage
during transportation. It is also a good idea to note the location of
the fossil collection on a map and/or in a fieldbook in order to make
it easier to find again if the need arises.
Note: Fossil collecting is illegal in National and Provincial
Parks and Ecological Reserves, unless you have special permits.
Identifying Fossils
Fossil species are generally identified by comparing collected
specimens with those illustrated in drawings and/or photographs in
publications. Generally, if a specimen cannot be identified in this
way, it is probably a new species.
When fossil genera or species have not been formally defined in
scientific publications, they are known as gen., sp.,
spp. or sp. nov., standing for genus, species (singular),
species (plural) and new species, respectively. Generic names enclosed
by quotation marks ("Agnostus") are meant to be informal,
and the abbreviation cf. means "similar to but not neccessarily
identical to".
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What Makes it Hard to Identify Fossils?
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Compaction of sediment. Clay muds compact more than lime muds.
Consequently, fossils preserved in shale commonly are flattened,
their shells cracked and or broken. Fossils preserved in limestone,
on the other hand, often retain their original shape and convexity,
and are not flattened at all. Sometimes flattened and nonflattened
individuals of the same species have been described as different
species.
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Different growth stages. Certain fossil organisms (i.e.,
trilobites, graptolites, corals) changed their shape throughout
their lifetimes. There are documented examples of different growth
stages of the same animal being described as separate species.
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Injuries. There have been examples in the paleontological
literature where injured trilobites of a particular species have
been described as a new species.
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Deformation of rocks. When rocks get folded and faulted, everything
in them, including fossils, gets deformed. Occasionally, deformed
and undeformed individuals of the same species have been described
as different species.
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| For further information on fossils please
contact
Doug Boyce
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