The document defines key terms related to various periods in geological time from the Cambrian through the Permian, including important locations, organisms, events, rock units, and processes. Terms are defined for archaeocyathids, bioturbation, the Burgess Shale, the Cambrian explosion, the Iapetus Ocean, trilobites, periods of the Paleozoic era, passive margins, and more.

1. ·
archaeocyathid
o
Cambrian - sessile, reef-building marine organisms of warm
tropical and subtropical waters that lived during the early
(lower) Cambrian period.
·
bioturbation
o
Cambrian - the reworking of soils and sediments by animals or
plants. Its effects include changing texture of sediments
(diagenetic), bioirrigation and displacement of microorganisms
and non-living particles. Common bioturbators include annelids
and bivalves (mussels, clams, gastropods).
·
Burgess Shale
o
Cambrian - located in the Canadian Rockies of British
Columbia, is one of the world's most celebrated fossil fields. It
is famous for the exceptional preservation of the soft parts of its
fossils. At 505 million years (Middle Cambrian) old, it is one of
the earliest fossil beds containing soft-part imprints.

2. ·
Cambrian explosion
o
Cambrian - the relatively rapid appearance, around 530 million
years ago, of most major animal phyla, as demonstrated in the
fossil record, accompanied by major diversification of
organisms
·
Iapetus Ocean
Cambrian/Ordovician - Precursor to the Atlantic. An ocean that
existed in the Neoproterozoic and Paleozoic eras of the geologic
timescale (between 600 and 400 million years ago). The ocean
disappeared with the Caledonian, Taconic and Acadian
orogenies, when these three continents joined to form one big
landmass called Laurussia.
maturity Cambrian
·
Paleozoic Era
o
Cambrian - the earliest of three geologic eras of the
Phanerozoic Eon, spanning from roughly 541 to 252.2 million
years ago. It is the longest of the Phanerozoic eras, and is
subdivided into six geologic periods (from oldest to youngest):
the Cambrian, Ordovician, Silurian, Devonian, Carboniferous,

3. and Permian.
·
passive margin
o
Cambrian - the transition between oceanic and continental crust
which is not an active plate margin. It is constructed by
sedimentation above an ancient rift, now marked by transitional
crust. Continental rifting creates new ocean basins.
·
trilobite
o
Cambrian - extinct marine arthropods that form the class
Trilobita. Trilobites form one of the earliest known groups of
arthropods. Trilobites finally disappeared in the mass extinction
at the end of the Permian about 250 million years ago. The
trilobites were among the most successful of all early animals,
roaming the oceans for over 270 million years.
·
bentonites
o
Ordovician - essentially impure clay consisting mostly of
montmorillonite. Bentonite usually forms from weathering of
volcanic ash, most often in the presence of water. However, the
term bentonite, as well as a similar clay called tonstein, has
been used to describe clay beds of uncertain origin.

4. ·
Cincinnati arch
o
Ordovician - when continents crashed together during the two
orogeny's you have the Appalachian mountains and then a down
drop into the Appalachian basin going west and then going west
the next rise is the Cincinnati arch and the next basin is the
Illinois basin.
epeiric (=epicontinental) seas Ordovician - a shallow sea
that covers central areas of continents during periods of high
sea level that result in marine transgressions.
·
exotic terranes
o
Ordovician - a fragment of crustal material formed on, or
broken off from, one tectonic plate and accreted or "sutured" to
crust lying on another plate. The crustal block or fragment
preserves its own distinctive geologic history, which is different
from that of the surrounding areas – hence the term "exotic"
terrane. The suture zone between a terrane and the crust it
attaches to is usually identifiable as a fault.
·
foreland basin
o

5. Ordovician - a depression that develops adjacent and parallel to
a mountain belt. Foreland basins form because the immense
mass created by crustal thickening associated with the evolution
of a mountain belt causes the lithosphere to bend
·
Great Ordovician Biodiversification Event (GOBE)
o
Ordovician - A diversification of animal life throughout the
Ordovician period, just 40 million years after the Cambrian
explosion, whereby the distinctive Cambrian fauna fizzled out
to be replaced with a Palaeozoic fauna rich in suspension feeder
and pelagic animals.
·
Queenston clastic
o
wedge ("delta") Ordovician - 300-mile-wide clastic wedge of
sediment deposited over what is now eastern North America
during the late Ordovician period due to the erosion of
mountains created during the Taconic orogeny. The wedge is
thickest in a band running from New York State to Quebec and
extends from the Catskill mountains to Lake Huron.
·
Taconic orogeny
o

6. Ordovician - a mountain building period that ended 440 million
years ago and affected most of modern-day New England. A
great mountain chain formed from eastern Canada down through
what is now the Piedmont of the East coast of the United States.
As the mountain chain eroded in the Silurian and Devonian eras,
sediments from the mountain chain spread throughout the
present-day Appalachians and midcontinental North America.[
·
barred (or restricted)
o
basin Silurian - A partially restricted sedimentary basin,
where free movement of waters is impeded by the presence of a
rock sill or sediment barrier. This restriction often results in
anoxic or oxygen-poor waters, or, in arid areas, in evaporite
deposition.
·
dolomite Silurian - Carbonate mineral
·
dolostone Silurian
o
a rock composed predominantly of the mineral dolomite with a
stoichiometric ratio of 50% or greater content of magnesium
replacing calcium, often as a result of diagenesis. Limestone
that is partially replaced by dolomite is referred to as dolomitic
limestone, or in old U.S. geologic literature as magnesian
limestone.

7. ·
eurypterid Silurian –
o
an extinct group of arthropods related to arachnids which
include the largest known arthropods that ever lived. They are
members of the extinct order Eurypterida (Chelicerata); which
is the most diverse Paleozoic chelicerate order in terms of
species.
Salina Group – salt, gypsum Silurian
·
stromatoporoids Silurian –
o
a class of aquatic invertebrates common in the fossil record
from the Ordovician through the Cretaceous. They were
especially abundant in the Silurian and Devonian. They are
useful markers whose form and occurrence can diagnose the
depositional environment of sedimentary strata
·
Acadian orogeny Devonian –
o
a middle Paleozoic mountain building event (orogeny),
especially in the northern Appalachians, between New York and
Newfoundland. The Acadian orogeny most greatly affected the

8. Northern Appalachian region (New England northeastward into
the Gaspé region of Canada). The Acadian orogeny should not
be regarded as a single tectonic event, but rather as an orogenic
era. It spanned a period of about 50 million years, from 375 to
325 million years ago.
·
Berea Sandstone Devonian –
o
Traditionally, the Berea was considered to be of Mississippian
age but recently it has been assigned a Late Devonian age. The
Berea formed when sand was carried by streams into the Ohio
sea from the Canadian Shield to the north and from the Catskill
Delta to the east.
·
Catskill clastic wedge Devonian –
o
a unit of mostly terrestrial sedimentary rock found in
Pennsylvania and New York. The Catskill is the largest bedrock
unit of the Upper Devonian in northeast Pennsylvania and the
Catskill region of New York
Columbus Limestone Devonian - a mapped bedrock unit
consisting primarily of fossiliferous limestone, and it occurs in
Ohio, Pennsylvania, and Virginia in the United States, and in
Ontario, Canada. Shallow marine depositional environment.
Hunsruck Slate Devonian - ower Devonian

9. lithostratigraphic unit, a type of rock strata, in the German
regions of the Hunsrück and Taunus. It is a lagerstätte famous
for exceptional preservation of a highly diverse fossil fauna
assemblage.
Lagerstatta Devonian/Pennsylvanian - a sedimentary
deposit that exhibits extraordinary fossils with exceptional
preservation—sometimes including preserved soft tissues. These
formations may have resulted from carcass burial in an anoxic
environment with minimal bacteria, thus delaying
decomposition. Lagerstätten span geological time from the
Cambrian period to the present.
Ohio Shale Devonian - late Devonian unit; dark black shale
that has a lot of organics, pyrite, sulfur, carbon; thought to
represent a very stagnant ocean-type bottom
rain shadow Devonian - dry area on the lee back side of a
mountainous area. The mountains block the passage of rain-
producing weather systems casting a "shadow" of dryness
behind them
Archimedes Mississippian - index fossil of Mississippian
Bedford = Salem = Indiana Limestone Mississippian - a
geological formation primarily quarried in south central
Indiana, United States between Bloomington and Bedford. The
limestone was deposited over millions of years as marine fossils
decomposed at the bottom of a shallow inland sea which
covered most of the present-day Midwestern United States
during the Mississippian Period.
Black Hand Sandstone Mississippian - Blackhand
Sandstone was formed over 300 million years ago when most of
Ohio was covered by a shallow sea. Sand was eroded from
distant mountains and floated down the streams into Ohio’s sea

10. where it collected in a long, narrow delta. Then, the currents
changed, and for a while the sands were deposited into the delta
at an angle. This created what is called cross-bedding. When the
currents returned to normal, the sand was once again deposited
in the delta in flat, horizontal layers. Fine sand and silt was
deposited over top of the heavy sands and buried it. The heavy
weight of this covering compressed the heavy sands. As
groundwater, with iron oxide in it, seeped through the layers of
heavy sands the iron cemented the sands grains into solid rock.
The groundwater slowly washed away the cement holding the
particles of sand together and eventually began washing away
the sand itself.
bryozoa Mississippian - a phylum of aquatic invertebrate
animals.
eustatic Mississippian - denoting or relating to worldwide
changes in sea level, caused by the melting of ice sheets,
movements of the ocean floor, sedimentation, etc.
Appalachian (Allegheny) Orogeny Pennsylvanian -
geological mountain-forming events that formed the
Appalachian Mountains and Allegheny Mountains. Occurred
over at least five deformation events in the Carboniferous to
Permian period. The orogeny was caused by Africa colliding
with North America.
cyclothems Pennsylvanian - alternating stratigraphic
sequences of marine and non-marine sediments, sometimes
interbedded with coal seams.
forams (incl. fusilinids) Pennsylvanian - The Fusulinida is
an extinct order within the Foraminifera in which the tests
(shells) are composed of tightly packed, secreted microgranular
calcite. In advanced forms the test wall is differentiated into
two or more layers. Loeblich and Tappan, 1988, gives a range

11. from the Lower Silurian to the Upper Permian, with the
fusulinid foraminifera going extinct with the Permian–Triassic
extinction event.
Joggins, Nova Scotia Pennsylvanian - contains an
unrivalled fossil record preserved in its environmental context,
which represents the finest example in the world of the
terrestrial tropical environment and ecosystems of the
Pennsylvanian 'Coal Age' of the Earth's history.
Lepidodendron Pennsylvanian - known as scale trees —
were a now extinct genus of primitive, vascular, arborescent
(tree-like) plant related to the lycopsids (club mosses). They
were part of the coal forest flora.
Linton, Ohio Pennsylvanian
Mazon Creek, Illinois Pennsylvanian - conservation
lagerstätte. The fossil beds are located in ironstone concretions,
formed approximately 300 million years ago in the mid-
Pennsylvanian epoch of the Carboniferous period. These
concretions frequently preserve both hard and soft tissues of
animal and plant materials, as well as many soft-bodied
organisms that do not normally fossilize.
Milankovich cycles Pennsylvanian - the collective effects
of changes in the Earth's movements upon its climate
ammonoid/ammonite Permian Period - an extinct group of
marine invertebrate cehalopods. Ammonites are excellent index
fossils, and it is often possible to link the rock layer in which
they are found to specific geological time periods. Their fossil
shells usually take the form of planispirals, although there were
some helically spiraled and nonspiraled forms (known as
heteromorphs).

12. amnion/amniote/amniotic egg Permian Period - a group of
tetrapods (four-limbed animals with backbones or spinal
columns) that have an egg equipped with an amnios, an
adaptation to lay eggs on land rather than in water as
anamniotes do.
archosaurs Permian Period - group of diapsid amniotes
whose living representatives consist of birds and crocodilians.
This group also includes all extinct non-avian dinosaurs, many
extinct crocodilian relatives, and pterosaurs.
cephalopods Permian Period - became dominant during the
Ordovician period, represented by primitive nautiloids. The
class now contains two, only distantly related, extant
subclasses. Any member of the molluscan class Cephalopoda.
These exclusively marine animals are characterized by bilateral
body symmetry, a prominent head, and a set of arms or tentacles
(muscular hydrostats) modified from the primitive molluscan
foot.
diapsids Permian Period - a group of Tetrapods that
developed two holes (temporal fenestra) in each side of their
skulls, about 300 million years ago during the late
Carboniferous period.[1] Living diapsids are extremely diverse,
and include all crocodiles, lizards, snakes, tuataras, and birds.
While some diapsids have lost either one hole (lizards), or both
holes (snakes), or have a heavily restructured skull (modern
birds), they are still classified as diapsids based on their
ancestry.
Dunkard Group Permian Period - an area of rock, Early
Permian in age, in the south of Ohio, southwestern
Pennsylvania, West Virginia and the hilltops of the Georges
Creek Basin of Maryland. It is one of the few areas of Permian
sediment east of the Mississippi River. In addition, it is the
youngest surface rock in the state of Ohio.

13. nautiloid Permian Period - a large and diverse group of
marine cephalopods (Mollusca) that began in the Late Cambrian
and are represented today by the living Nautilus and
Allonautilus. Nautiloids flourished during the early Paleozoic
era, where they constituted the main predatory animals, and
developed an extraordinary diversity of shell shapes and forms.
Serpent Mound Structure Permian Period - a 1,348-foot-
long, three-foot-high prehistoric effigy mound located on a
plateau of the Serpent Mound crater along Ohio Brush Creek in
Adams County, Ohio.
synapsids Permian Period - group of animals that includes
mammals and every animal more closely related to mammals
than to other living amniotes. They are easily separated from
other amniotes by having a temporal fenestra, an opening low in
the skull roof behind each eye, leaving a bony arch beneath
each
therapsids Permian Period - a group of the most advanced
synapsids, and include the ancestors of mammals. Many of the
traits today seen as unique to mammals had their origin within
early therapsids, including an erect posture and lactation. Early
Permian–Early Cretaceous
anoxia Mass extinctions - a total depletion in the level of
oxygen, an extreme form of hypoxia or "low oxygen"
Permo-Triassic Mass extinctions - 80-90% extinction –
took 5-6 million years to recover.
Siberian Traps Mass extinctions - form a large region of
volcanic rock, known as a large igneous province, in the
Russian region of Siberia. The massive eruptive event which
formed the traps, one of the largest known volcanic events of

14. the last 500 million years of Earth's geological history,
continued for a million years and spanned the Permian–Triassic
boundary, about 251 million to 250 million years ago.
labyrinthodont Fish - an extinct amphibian subclass, which
constituted some of the dominant animals of late Paleozoic and
early Mesozoic eras (about 360 to 150 million years ago). The
group is ancestral to all extant landliving vertebrates.
ostracoderm Fish - the armored jawless fishes of the
Paleozoic.
placoderm Fish - among the first jawed fish. A class of
armoured prehistoric fish, which lived from the mid Silurian to
the end of the Devonian period. Their head and thorax were
covered by armoured plates; the rest of the body was scaled or
naked, depending on the species.
tetrapod Fish - the first four-limbed vertebrates and their
descendants, including the living and extinct amphibians,
reptiles, birds, and mammals. Likely did not live on land.
body fossil Fossil Preservation - most common are from the
hard parts of the body, including bones, claws and teeth. More
rarely, fossils have been found of softer body tissues.
cast Fossil Preservation - A fossil formed when an animal,
plant, or other organism dies, its flesh decays and bones
deteriorate due to chemical reactions; minerals gradually enter
into the cavity, resulting in a cast
coprolite Fossil Preservation - fossilized feces. Coprolites
are classified as trace fossils as opposed to body fossils, as they
give evidence for the animal's behaviour (in this case, diet)
rather than morphology.

15. dendrite Fossil Preservation - pseudofossils – a naturally
occurring object that looks like a fossil but isn’t. Dendrites are
twig-like looking things that are a mineral growth but look like
fossils. NOT FOSSILS. Most dendrites are mangenise-oxides so
they’re black
fossil Fossil Preservation - the preserved remains or traces
of animals (also known as zoolites), plants, and other organisms
from the remote past.
mold Fossil Preservation - Molds and casts are types of
fossils. When a dead organism is buried, it often decays
completely, leaving behind only an impression in the rock in the
form of a hollow mold. The hard parts are most likely to leave
an impression, although sometimes so can soft parts. If the mold
then fills with sediment, this can also harden, forming a
corresponding cast.
paleontology Fossil Preservation - the scientific study of
prehistoric life. It includes the study of fossils to determine
organisms' evolution and interactions with each other and their
environments.
pseudofossil Fossil Preservation – a naturally occurring
object that looks like a fossil but isn’t.
recrystallization Fossil Preservation - a metamorphic
process that occurs under situations of intense temperature and
pressure where grains, atoms or molecules of a rock or mineral
are packed closer together, creating a new crystal structure. The
basic composition remains the same.
replacement Fossil Preservation - a form of fossilization in
which the original organic material is gone and is replaced by
mineral material. The most common/famouse is pyritization.
Ohio is famous for pyritized brachiopods

16. steinkern Fossil Preservation - if you fill the hollow area of
a shell with sediment and the shell rots away, the cast of
sediment that is left over is the stinecurn (spelling)
trace fossil Fossil Preservation - geological records of
biological activity. Trace fossils may be impressions made on
the substrate by an organism: for example, burrows, borings
(bioerosion), urolites (erosion caused by evacuation of liquid
wastes), footprints and feeding marks, and root cavities.
conodont alteration index (CAI) Nonbio info from fossils -
used to estimate the maximum temperature reached by a
sedimentary rock using thermal alteration of conodont fossils.
Conodonts in fossiliferous carbonates are prepared by
dissolving the matrix with acid, since the conodonts are
composed of apatite and thus do not dissolve. The fossils are
then compared to the index under a microscope. The CAI is
commonly used by paleontologists due to its ease of
measurement and the abundance of Conodonta throughout
marine carbonates of the Paleozoic.
conodonts Nonbio info from fossils - extinct chordates
resembling eels, classified in the class Conodonta. For many
years, they were known only from tooth-like microfossils now
called conodont elements, found in isolation. Knowledge about
soft tissues remains relatively sparse to this day.
diversity gradient Nonbio info from fossils - The increase
in species richness or biodiversity that occurs from the poles to
the tropics, often referred to as the latitudinal diversity gradient
(LDG), is one of the most widely recognized patterns in
ecology. Put another way, in the present day localities at lower
latitudes generally have more species than localities at higher
latitudes. The LDG has been observed to varying degrees in
Earth's past.

17. Ohio Clay ohio was once the clay/brick capital of the world
Fauna