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U.S. DEPARTMENT OF THE INTERIOR 

U.S. GEOLOGICAL SURVEY

Make Your Own Paper Fossils

A computer animation and paper models

By

Tau Rho Alpha*, Scott W. Starratt*, and James W. Hendley H* 

Open -file Report 94-667

This report is preliminary and has not been reviewed for conformity 

with U.S. Geological Survey editorial standards. Any use of trade, 

firm, or product names is for descriptive purposes only 

and does not imply endorsement by the U.S. Government.

Although this program has been used by the U.S. Geological Survey, 

no warranty, expressed or implied, is made by the USGS 

as to the accuracy and functioning of the program 

and related program material, nor shall the fact of 

distribution constitute any such warranty,

and no responsibility is assumed 

by the USGS in connection therewith.

*U.S. Geological Survey 

Menlo Park, CA 94025

Comments encouraged

talpha@ISDMNL.wr.usgs.gov

sstarratt@ISDMNL.wr.usgs.gov

jhendley @b wtrms. wr.usgs. gov
(gobackvwd) <(n| H^ (gofoxwd)

Description of Report

This report illustrates, by means of computer animations and paper 

models, how two organisms, a trilobite and a nautiloid, became fossils. The 

report is intended to help students and others visualize the size and shape 

of a trilobite and a nautiloid, the environment in which they lived, and the 

circumstances of their fossiUzation and subsequent discovery. By studying 

the animations and the paper models, students will come to understand 

why fossils are important in interpreting the Earth's history.

Included in the diskette version of this report are templates for making 

the paper models, and instructions for their assembly, a discussion of 

fossils, and animations of trilobite and nautiloid locomotion and habitats.

The animation is accompanied by sound. If no sound is heard, change 

the memory of HyperCard, to 4500K, and ensure that the control panel 

"Sound", which is in the "Control Panels" folder under the "Apple" menu, 

has the volume set to at least 2. To change the memory available to 

HyperCard quit this stack. Highlight the HyperCard, program icon and 

choose "Get Info" from the File Menu. Change the "memory 

requirements" to 4500K and start this stack again. The paper version of 

this report includes everything listed above except for the animations.

Many people provided help and encouragement in the development of 

this HyperCard stack, particularly Dan Jensen, Art Ford, and Lisa Baserga. 

This report was enhanced by the excellent reviews by Ron Le Compte, 

Will Elder, and Jim Pinkerton.
(go backvard) <(~]| L^ (goforvaid)

Description of Report

Requirements for the diskette version are: Apple Computer, Inc., 

HyperCard 2.2 software and an Apple Macintosh computer with a 

high-density drive. If you are using System 7, we recommend using at 

least 3 MB of RAM with 4500K of memory available for HyperCard. To 

change the memory available to HyperCard, quit this stack. Highlight the 

HyperCard program icon and choose "Get Info" from the File Menu. 

Change the "memory requirements" to 4500K and start this stack again.

Purchasers of the diskette version of this report, which includes all of 

the text and graphics, can use HyperCard 2.2 software (not supplied) to 

change the model (by adding geologic patterns, symbols, colors, etc.) or 

to transfer the model to other graphics software packages.

To see the entire page (card size: MacPaint), select "Scroll" from 

the"Go" menu and move the hand pointer in the scroll window. If you are 

experiencing trouble with user-level buttons, select "message" from the 

"Go" menu. Type "magic" in the message box and press return. Three 

more user-level buttons should appear.

The date of this Open File Report is 11/28/1994. OF 94-667-A, paper 

copy, 42p.; OF 94-667-B, 3.5-in. Macintosh 1.4-MB high-density 

diskette.

To order this report, contact:

USGS ESIC-Open-File Report Section 

Box 25286, MS 517 

Denver Federal Center 

Denver, CO 80225-0046

or call (303)-236-4476.
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LEARN ABOUT FOSSILS

The first evidence of human interest in fossils dates back at least 15,000 

years. Scientists have found a layer of dirt in a cave in France that, along with 

artifacts of human occupation, contains a number of trilobite fossils with holes 

drilled into them. These trilobite fossils may have been worn as jewelry and 

were probably obtained through trade with other groups of people from far 

away, because no similar fossils have been found anywhere else in France. In 

the Western United States, the Ute Indians collected fossilized specimens of 

the trilobite Elrathia (commonly used today as refrigerator magnets) with 

which they made fetishes or charms. The Utes called the fossil trilobites 

"timpe khanitzapachavee," which in their language means "little water bug 

like stone house in" (Boardman and others, 1987). The Aborigines of 

Australia used trilobite-bearing flint as tools. In Europe, Asia, and South 

America, trilobite fossils were often made into jewelry. Today, they are 

probably the most commonly sought-after fossils by amateur fossil collectors 

around the world.

What is a Fossil?

When you find a fossil you have found something that is interesting but 

also something that represents a piece of the Earth's history. Fossils are a 

window into the life of the past. A fossil is any evidence (bodily remains or 

trace) of a plant or animal that has been preserved in Earth's crust since some 

past geologic age. More loosely defined, a fosssil is any evidence of past life. 

The structure of the fossil can tell you about where it might have lived (if you 

found a fossil of a fish, you would probably guess that it didn't live on land) 

or what it ate (if you found a fossil crab, you would probably guess that it 

didn't eat rabbits). Sometimes you don't find an actual fossil (sometimes 

called a body fossil), but you find evidence of how an organism behaved 

(trace fossils). Trace fossils include things like worm trails and dinosaur 

footprints.

The rock in which a fossil is found can also tell you something about the 

environment in which the fossilized organism lived. Trilobite fossils are 

usually found in fine-grained rocks that were once mud. Because the mud 

did not contain sand or pebbles, we believe that it was probably deposited in 

a quiet place, like the bottom of the ocean. Over a long period of time, the 

gooey mud turned into stone.

O
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The Making of a Fossil

Around the world, from the bottom of the ocean to high mountain lakes, 

you can find evidence of living organisms and their activities. But how much 

of this evidence of life will survive beyond today to become the fossils of 

tomorrow? It has been suggested that of the more than one million living 

animal species, somewhat fewer than 10 percent will be preserved as fossils. 

The preservation of a fossil is a rare event; when you look at the fossil record 

as a whole, it is incomplete, and individual fossil species are probably either 

over or under represented, even under the best conditions.

The likelihood of preservation of an organism (body fossil) or the 

preservation of the evidence of its activities (trace fossils) depends on several 

factors. These include (1) what the organism was made of, (2) how many of 

the organisms there were, (3) what type of environment the organisms lived in 

or, even more important, what type of environment they died in, and (4) what 

happened to them after they were buried.

The key to the preservation of a an organism as a fossil is its resistance to 

destruction. In general, organisms are made up of two kinds of parts, soft 

parts and hard parts. Soft parts decay rapidly after death, and there is little 

fossil evidence of organisms that were made up entirely of soft tissue (that is 

why trace fossils are usually the only record of earthworms or slugs). On the 

other hand, bones, teeth, shells, and the like are hard parts and-not subject to 

decay after death. Once the hard parts get buried, they may eventually form a 

body fossil.

Another factor in fossilization is luck. Everything else being equal, the 

greater the number of individual plants or animals there are, the greater the 

likelihood that some of those organisms will be preserved as fossils.

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A description of the environment in which an organism lived and (or) 

died includes such factors as sediment type (sand or mud), how fast the 

sediment was deposited, and how much energy (currents, storm waves, etc.) 

there was stirring up the sediments, as well as where the organism lived (in 

the sediment, on top of the sediment, or swimming around above the 

sediment). Some sedimentary environments have a better chance of being 

preserved than others. This, in turn, influences the chances of fossilization of 

the organisms that live in those environments.

The final factor in fossil preservation is what happens to the organism after 

it is buried. Sometimes the shell of the organism is dissolved away, leaving a 

mold or impression of the shell. These molds may be then filled with 

fine-grained sediment (usually clay) at a later time, forming what is called a 

cast. If the shell is not totally dissolved over a long period of time, minerals in 

the ground water moving through pores in the rock can replace the original 

shell or bone material with other minerals.

When one considers all of the things that can adversely affect the 

fossilization process, it is no surprise that the fossil record is so poor. 

Remember that such spectacular fossil finds as insects in amber, 

Archeopteryx (what most scientists consider the earliest bird), and complete 

dinosaurs are extremely rare and represent only a glimpse into the variety of 

life that existed in the Earth's past.

Trilobites

For many million years during the Paleozoic Era, trilobites were one of 

the most common organisms that lived on or in mud on the shallow sea floor 

Some of the smallest trilobites, rather than living on the sea floor like most of 

their larger relatives, probably swam or floated in surface waters. Today, 

trilobite fossils can be found (as magnets) on refrigerators around the world, 

holding up shopping lists or a child's work of art.
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Trilobites were a part of a larger group of organisms called arthropods, a 

name which means "jointed foot". Living members of this group include 

crabs, lobsters, spiders, and, of course, insects. The importance of this group 

is its large number of individual animals and exceptional diversity 

(large number of species). The number of species of living insects is thought 

to be somewhere between one and two million. Although the actual diversity 

of easily fossilized arthropods is much lower than this number, the remains of 

these organisms still make up a substantial part of the fossil record.

Arthropods (usually trilobites) are important to geologists for two main 

reasons. First, the structure (or shape) of their bodies changed (evolved) over 

time. Because each trilobite shape appears only for a short period of time, 

rocks (say from the United States and China) containing similarly shaped 

trilobites are thought to be of about the same age. Second, because changes 

in body shape are often related to changes in the environment, fossils can be 

used for reconstructing ancient environments.

The available fossil record for the arthropods is strongly biased. This is 

because the external skeleton (or "shell") of the majority of arthropods 

(insects, spiders, most crabs, lobsters, and shrimp) is made up of a thin 

material that does not contain any minerals to make it hard. These "shells" 

do not fossilize very well. In a few groups, including trilobites, minerals are 

"built in" to the external skeleton, making it hard. These hard shells stand a 

much better chance of becoming fossils. A trilobite's chance of preservation 

was enhanced not only by its mineralized shell but also by the.fact that 

trilobites shed their shells as they grew, similar to snakes shedding their skin. 

Therefore, there were several opportunities for every trilobite to be preserved 

as a fossil.

The trilobite gets its name from the fact that its body is divided into three 

segments, or lobes. The central lobe is called the axial lobe, and the right and 

left lobes are called the pleural lobes. They are called the pleural lobes 

because they protect the trilobite's breathing organs, the gills. The trilobite is 

also divided into three parts from front to back. The cephalon (head), 

contains sensory organs like the eyes, antenna, and the mouth. The thorax 

(body) contains the internal organs. Most of the legs and the gills are 

attached to the thorax. The third part is the pygidium (tail).
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Each leg of the trilobite had two main parts. The longer part was used for 

walking. The shorter part, the gill, was attached to this "walking leg11 near the 

point where the leg joins the body. In addition to being used for walking and 

breathing, the legs closest to the mouth may also have been used to help 

gather food and move it toward the mouth. Most trilobites probably fed on 

small fragments of plant and animal matter in the sediment Some may have 

been scavengers, feeding off the carcasses of anything that settled to the sea 

floor. Others may have been predators, capturing small worms living in the 

sediment. A small number were planktonic (they floated near the surface of 

the ocean) and probably fed on bits of plant and animal material floating in 

the ocean waters.

Not much is known about the internal anatomy of trilobites. Because 

most of the internal parts were soft, they did not fossilize. Much of what we 

know about their anatomy and function is based on comparisons with 

modern arthropods, such as shrimp and lobsters.

As time passed in the Paleozoic sea, more predators threatened the 

trilobite. Available information suggests that the legs of the trilobite did not 

provide much speed or maneuverability to help escape from their enemies. In 

order to defend themselves, some trilobites rolled themselves into little balls, 

much like the armadillo does today.

Pygidium

(tail)

Thorax

(body)

Cephalon

(head)

Pygidium

(tail)

Thorax

(body)

Cephalon

(head)

pleura] lobe:

: axial lobe:

TOP BOTTOM

legs

TRILOBITE
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Nautiloids

Few who have read Jules Verne's "20,000 Leagues Under the Sea" will 

forget the giant squid that threatened to destroy Captain Nemo and the crew 

of the Nautilus. For millions of years, these giant denizens of the deep and 

their relatives have swum the ocean depths. The giant squid is part of a larger 

group, the cephalopods (a name which means "head foot"). Present-day 

members of this group include the octopus, cuttlefish, squid, and the beautiful 

chambered nautilus, which lives in the southwestern part of the Pacific Ocean. 

This group also included the now-extinct ammonite.

As a group, cephalopods are the largest, most intelligent, and most agile 

of the mollusks (a group that also includes clams, slugs, and snails). Some 

individuals can reach speeds of 70 kilometers per hour (42 miles per hour). 

The eyes of some cephalopods are similar to those found in vertebrates, such 

as fish, reptiles, and mammals.

Today, nautiloids are represented by five types of chambered nautilus. In 

nautiloids, the "foot" has been modified into a funnel or hyponome (used to 

produce a water jet for propulsion) and into as many as 94 tentacles. Unlike 

the octopus and squid, the chambered nautilus lacks an ink sac. It must rely 

on speed and its shell for protection from predators.

ene * head

shell i

tentacles \ OUTSIDE

hyponome

septum

camera cameral deposits

NAUTILOID

siphon INSIDE
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In the past, many types of cephalopods had shells covering the outsides 

of their bodies, but most of these shell-bearing types became extinct by the 

end of the Cretaceous Period. Today, only the nautiloids (unlike squids and 

most octopuses) have a shell covering the outsides of their bodies. (The 

females of one octopus type, called Argonauta, produce a paper-like shell in 

which they carry their eggs.) The shell is the most commonly fossilized part 

of the nautiloid. Many different shapes have been found in the fossil record, 

with the most common are long cones. As a nautiloid grows, the inside of the 

shell is divided into a series of camerae (chambers; a single chamber is called 

a camera) and the sizes of the camerae also increase. The chambers that over 

time became too small for the animal to live in are sealed off with a chamber 

wall or septum. The outside of the shell is usually smooth; sometimes the 

sutures, shallow groves which correspond to the location of a septum, are 

visible. The siphon runs through the interconnected chambers. The siphon 

allows the animal to regulate its buoyancy by controlling the amount of gas 

or liquid in each camera; thus, it is able to control its depth in the ocean by 

varying the amount of air in its shell, in much the same way that a submarine 

alternately dives and rises to the surface of the ocean. As its body continues 

to grow it is often necessary for the nautiloid to deposit shell material 

(cameral deposits) in some of the camerae in order to balance the weight of 

the increased body mass.

During the Paleozoic Era, most nautiloids and their relatives, the 

ammonites, were probably free-swimming marine predators or scavengers. 

They were probably not very choosy about what they ate, but trilobites 

probably were a part of their diets.

As is the case with the trilobites, nautiloids and their relatives were most 

common in the warm shallow oceans of the Paleozoic Era. Over the past 500 

million years, most species of nautiloids became extinct (the last of the 

ammonites became extinct at the same time as the dinosaurs, that is, at the 

end of the Cretaceous Period).
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One interesting characteristic of cephalopod evolution is a tendency 

toward gigantism. Tales of giant sea monsters date back to the epic poems of 

the ancient Greeks. There have been reports of giant squid (kraken) more 

than 22 meters (66 feet) long; giant octopi (devilfish) are known to exceed 25 

meters (75 feet). The longest fossil straight cephalopod shell is about 10 

meters (30 feet) (and that doesn't include the body and tentacles); the largest 

coiled ammonite fossil has a shell diameter of 3 meters (9 feet) [uncoiled, it 

would be more than 18 meters (59 feet) long].

Trace Fossils

The study of trace fossils is often jokingly called "fossil psychology," 

because the evidence that is studied represents the behavior of the organisms, 

not the organisms themselves. Trace fossils have several advantages over 

body fossils: (1) they are often preserved in rocks (like sandstone) where 

body fossils are not usually preserved, (2) the physical and chemical 

processes that often destroy the bodies of organisms after they die do not 

usually affect trace fossils, and (3) because trace fossils are formed on or 

within the sediment, they are found where the animals that made them 

actually lived. The main problem with using trace fossils is that is it difficult to 

make a direct connection between the body fossil and its associated trace 

fossil. The animation sequence in this report illustrates an extremely rare 

event, one where the trilobite "died in its tracks."

Trace fossils convey evidence of a number of different behaviors, including 

resting or hiding, locomotion (our trilobite), and dwelling and (or) feeding 

(within burrows and on the surface of the sea floor). Because we know that 

certain kinds of animals make specific traces in modern sediments, geologists 

can use this information in their interpretation of traces preserved in 

sediments formed in past environments.

Trace fossils can also tell us about the history of life. The oldest trace fossils 

are almost 2 billion years older than the oldest body fossils. It is interesting to 

note that although thousands of species of animals have come and gone over 

the past 570 million years, the number of kinds of trace fossils has not 

changed much. This indicates that animal behavior (feeding, moving, and 

resting) has not changed much over time even though the types of organisms 

have.
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Sedimentary Environments

Fossilized evidence of life can be found around the world. The evidence 

ranges from enormous dinosaur fossils found in ancient stream channels and 

swamps to the tiny skeletons of single-celled plants and animals that once 

lived in the surface waters of the oceans. Trilobites and nautiloids fall 

somewhere between these two size extremes.

In the section entitled "The Making of a Fossil," the requirements for fossil 

formation are briefly discussed. A discussion of all the possible sedimentary 

environments that contain fossils is beyond the scope of this guide, so we will 

restrict our present discussion to the sedimentary depositional environment 

with which our the trilobite and nautiloid in our animation are associated.

The floor of the deep ocean is a dark and relatively quiet place. Most of 

the sediment (including the bodies of animals) "rains" down from the waters 

above. This "rain" of sediment is usually very gentle. Once the sediment 

reaches the sea floor, most of it remains where it lies. In some places, nonstop 

deep-ocean currents continually remove the finest grained sediment. This 

process is very slow [millimeters (a fraction of an inch) per year in some 

places]. This little-changing "rain" of sediment is an illustration of one of the 

basic principles of geology, the "Principle of Uniformitarianism."

In the accompanying animation, we have also illustrated the opposite 

extreme in sedimentary deposition, the rare catastrophic event. In the blink of 

an eye, a catastrophic "event" can deposit several meters (feet) of sediment.

"Uniformitarian" sedimentary deposition (a gentle "rain" of sediment) is a 

process that can take tens to hundreds of years to bury the body of an 

organism (in this case, a nautiloid). The trilobite was less fortunate, however, 

as it was buried alive by a catastrophic depositional event (called a turbidity 

current). The "geologically instantaneous" nature of this event covered the 

trilobite with so much sediment that Paleozoic scavengers (among them other 

trilobites and nautiloids) were unable to feed on its body. That is why the 

body of the trilobite was fossilized in one piece.
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After the trilobite and nautiloid were buried, sediment continued to 

"rain" down over them for millions of years. As time passed, the increasing 

thickness of the sediment caused the ocean to become shallower. As the 

depth to the bottom of the sea floor became shallower, the composition of the 

sediments that was being deposited there changed. In deep water, the 

sediment consisted mostly of mud, whereas in shallow water it contained 

more sand. As the thickness of the sediment layers increased, so did their 

total weight. This great increase in weight helped to cause the mud and sand 

that once covered the sea floor to turn into solid rock.

Millions of years and thousands of meters (feet) of sediment later, dry land 

is formed over the site were the trilobite and nautiloid were buried.

Erosion

Once sediment and rocks are exposed at the Earth's surface, they are 

subject to the process of erosion. Wind and moving water (rain, streams, and 

rivers) are the main elements of erosion. Human activities sometimes work to 

speed up the erosion process.

Wind blows loose sediment from place to place. Sometimes, when that 

sediment is blown against rocks, bits of the rock are chipped off and carried 

away by the wind (the process is similar to sandblasting old paint off of a 

house).

Water works in much the same way as does the wind. Rain washes 

sediment into streams and then into rivers. These rivers dump most of their 

sediment into the ocean.

In a matter of hundreds or thousands of years, erosion can remove layers 

of sediment that took millions of years to form. Humans can accomplish the 

same thing in a local area in hours or days.
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Geologic Time

The length of time (or magnitude of time) in Earth history is one of the 

most difficult concepts to teach.

Around 600 B.C., Greek naturalists observed that shells on mountain tops 

a great distance inland were similar to those found living along the seashore. 

They also noted evidence that the sea had once covered part of the Island of 

Malta. They reasoned that the sea had once been present where the shells 

were found and that the position of the shoreline was constantly changing.

Leonardo da Vinci noted sea shells in the mountains of northern Italy. He 

reasoned that these rocks had once been mud at the bottom of the sea. He 

also suggested that the differences between the shells he found in the 

mountains and those he found on the beaches of Italy were due to the process 

of fossilization.

THE GEOLOGIC TIME SCALE

Eras

Cenozoic

( Recent life )

Mesozoic

( Middle life )

Paleozoic

( Ancient life )

Precambiian

Periods

qvjJtenujy

Tertiary

Cretaceous

Jurassic

Triassic

Permian

Pennsylvanian

Mississippi an

Devonian

Silurian

Ordovician

Cambrian

Millions of 

years ago

- 1.6

- 66.4

- 144

^Uo

245 t»T%y 

- OQfi ^oo 

320 *J£*\J

o£n jou

- 408

- /I^Q HOO

- 505 

570 j i \j

(The Earth is over 4 billion years old.)
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Ironically, the Roman occupation of Great Britain from the first century 

B.C. to the fourth century A.D. offered a clue to the age of the Earth. Near 

the end of the eighteenth century, members of the Royal Society of 

Edinburgh were thinking about the age of the Earth. They reasoned that 

since Hadrian's Wall (a structure that crosses northern Great Britain) was less 

than 1,000 years old and showed few signs of deterioration, the age of the 

Earth must be much greater than a few thousand years.

The early nineteenth century was a time of great cultural activity in 

England. The population was growing rapidly, and the Industrial Revolution 

was getting underway. The least expensive means for transporting goods 

from city to city was by horse-drawn barge. To do this, an elaborate system 

of canals had to be constructed. During the construction of these canals, the 

engineers began to notice that certain collections of fossils (called 

assemblages) were found in a certain order (for example, assemblage A was 

always found below assemblage B, no matter where the two assemblages 

were found).

Building on the ideas that older rocks were always overlain by younger 

rocks (Law of Superposition) and that less complex organisms were usually 

followed by more complex organisms (Faunal Succession), geologists and 

naturalists began to assign relative ages to the rocks. These geologists and 

naturalists found that it was possible to apply these fossil relationships around 

the world.

Throughout the nineteenth and early twentieth centuries an increasing 

number of naturalists and geologists, working all over the world, continued to 

refine this series of relative ages into a time scale. They found that as they 

refined the time scale, there were regional variations in the fossil successions 

(fossil successions in England did not always match those in North America). 

However, on the whole, the larger divisions of the time scale could be applied 

all over the world. Most of the divisions of the time scale are named for rocks 

that are found in Europe. Two of the divisions (Mississippian and 

Pennsylvanian Periods) were named for rocks that are present in the United 

States. In the middle of the twentieth century, analysis of radioactive 

elements that occur naturally in some rocks was used to give actual ages (in 

years) to the rocks, resulting in an absolute time scale.
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What's in it for me?

Fossils have many uses other than holding grocery lists on refrigerator 

doors. Geologists and paleontologists (a person who studies the history of 

life) use fossils to guide their search for oil and minerals. Oil is the product of 

the remains of thousands of ancient organisms, and fossils can be used to date 

the rocks where oil first formed and where it accumulates. Knowing the ages 

of the rocks and their distribution helps scientists decide where to drill for oil. 

Using fossils to date rocks located on both sides of a fault (a break in the 

Earth's surface along which there has been movement) can help geologists 

tell how long ago and how much a fault has moved. The "Theory of 

Evolution" is based in part on fossil evidence, and fossils can tell a lot about 

what life was like in the past. Archeologists use fossils to determine what 

kinds of food ancient people ate and what kinds of animals they raised. It's 

interesting to study trilobites because they are one of the most numerous 

animals ever to populate the Earth. Last, but not least, FOSSILS ARE 

FUN!!!
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Questions for further study

1. What organisms do you think might one day become fossils? Give reasons 

why.

2. Make a list of different environments (deep ocean, beach, river, and 

mountain top) and discuss whether or not fossils could form in each of these 

environments.

3. Can fossils be found on the top of a mountain, on the beach, or at the 

bottom of the ocean?

4. Which environments do you think have the best chance of preserving 

fossils. Give some reasons why?

5. Do you have a favorite fossil? Why is it your favorite?

6. What are some of the ways that fossils are formed?

7. Does your State have a State Fossil?

8. What part have fossils played in the development of the Theory of 

Evolution?

9. Is there a place near your home or school where fossils can be found?

10. Is there a place near your home or school where you can go to see 

fossils?

11. Why were trilobites so successful? Think about why their relatives, the 

insects, are so successful today.

12. Why do you think that trilobites and nautiloids are often found in one 

piece, whereas dinosaur skeletons are found scattered and with various pieces 

missing?
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Glossary

Ammonite A coiled cephalopod similar to a nautiloid. The name is derived 

from Ammon, an ancient Egyptian god. Since Ammon considered the ram 

(male sheep) to be divine, he is represented in ancient Egyptian mythology 

by the head of a ram, with twisted, spiral horns similar in shape to an 

ammonite shell.

Archeologist A person who studies the physical evidence of the history of 

Man. This often includes studing ancient ruins in exotic places, including 

under the sea.

Cambrian The earliest Period of the Paleozoic Era. It is thought to have 

spanned the period of time from about 570 to 505 million years ago. Derived 

from the word "Cambria", the Roman word for Wales, in the southwestern 

part of Great Britain.

Cenozoic The youngest Era, extending from the beginning of the Tertiary 

Period (about 66.4 million years ago) to the present. Paleontologically, it is 

characterized by the rapid evolution and abundance of mammals, mollusks, 

and birds. The terms "Recent Life" and "Age of Mammals" are sometimes 

used to refer to this Era.

Cretaceous The youngest Period of the Mesozoic Era. Thought to have 

spanned the time interval from about 144 to 66.4 million years ago. The last 

Period during which the dinosaurs existed. The term "Cretaceous" comes 

from "Creta", the Latin word for chalk, which is common in the sea cliffs of 

northeastern Great Britain ("white cliffs of Dover," if you're old enough to 

remember the hit song from the Second World War).

Denizen An inhabitant of a particular place. In this case, we are referring 

to the giant squid, octopuses, and other "monsters" that inhabit the deep, dark 

parts of the World's oceans.

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Glossary Cont.

Devonian A Period in the Paleozoic Era thought to have spanned the time 

interval from 408 to 360 million years ago. Named for the county of 

Devonshire, England where rocks of this age were first studied. Often 

referred to as the "Age of Fishes."

Era The largest (for our purposes) division of time. Each Era includes at 

least two Periods (for example, Cretaceous, Devonian), the next smallest 

division of geologic time.

Faunal Succession The idea that certain groups or assemblages of 

organisms precede or succeed each other. The members of the younger 

assemblage are usually more advanced (or complicated) than 

members of the older assemblage (for example, fish preceded dogs in the 

fossil record).

Fossil Any evidence of bodily remains or the trace of a plant or animal that 

has been preserved in the Earth's crust since some past geologic age. 

More loosely defined, a fossil is any evidence of past life.

Jurassic Middle Period of the Mesozoic Era. Spanned the interval of time 

from about 208 to 144 million years ago. It is named for the Jura Mountains, 

which are present in France and Switzerland.

Law of Superposition The law upon which the geologic time scale is 

based. It states that in any sequence (stack) of sedimentary rocks or strata 

(that has not been structurally modified, for example, overturned), the oldest 

rocks or sediments are present on the bottom.

Mesozoic The Era of geologic time that occurs between the Paleozoic Era 

and the Cenozoic Era. It is also called the "Age of Reptiles."
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Mississippian A Period in the Paleozoic Era that is thought to have 

covered the span of time from 360 to 320 million years ago. It is named after 

the Mississippi River valley, where there are extensive exposures of rocks of 

this age.

Ordovician The second oldest Period of the Paleozoic Era, spanning the 

time from 505 to 438 million years ago. It is named after the British Celtic 

tribe, the Ordovices. Because a large number of different kinds of organisms 

evolved in the shallow seas of the Ordovician, it is often called the "Age of 

Marine Invertebrates."

Organism Any individual form of organic life, plant, or animal.

Paleontologist A person who studies the history of life. This usually does 

not include the study of Man (see Archaeologist). Paleontologists usually 

study fossils in one of four major groups invertebrates (trilobites, 

nautiloids), vertebrates (dinosaurs), plants, or micro-organisms (diatoms, 

foraminifers).

Paleozoic The geologic Era that occurs between the Precambrian Era and 

the Mesozoic Era. Also referred to as the Era of "Ancient Life."

Pennsylvanian A Period in the later part of the Paleozoic Era, spanning 

the interval from 320 to 286 million years ago. It is named after the State of 

Pennsylvania, where many of the of rocks of this age contain layers of coal. 

Because the coal is from the deposits of fern forests and swamps, this Period 

is often referred to as the "Age of Coal."

Period The intermediate interval in the hierarchy of geologic time between 

an Era (longer) and an Epoch (shorter).

Permian The oldest Period of the Paleozoic Era, spanning the time interval 

from 286 to 245 million years ago. It is named after the Perm region of the 

Commonwealth of Independent States (the former U.S.S.R.). It is also called 

the "Age of Amphibians" because of the large number of skeletons of 

amphibians that have been found in swamp deposits of this age.

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Precambrian Ail geologic time before the Paleozoic Era. Rocks of this 

age generally carry no signs of multicellular forms of life. Spans the interval 

from 570 million years ago to the formation of the Earth, about 4.6 billion 

years ago.

Preservation The process by which the remains of an organism are saved.

Principle of Uniformitarianism One of guiding principles of geology. 

Geologic processes and natural laws operate in the same way today as they 

have in the past (gravity has always existed, and its strength has not changed 

through time). The classic statement of this concept is "the present is the key 

to the past."

Quaternary The last Period of the Cenozoic Era. Ranges in age from 

about 1.65 million years ago to the present day. Sometimes referred to as the 

"Age of Man."

Sediment Materials that are commonly called "dirt" or "mud." Sediment 

can consist of deposits of clay, silt, sand, pebbles, cobbles, and boulders.

Silurian A Period in the Paleozoic Era that spanned the interval between 

438 and 408 million years ago. Named for the Silures, a Celtic tribe in Great 

Britain.

Species A group of organisms, either plant or animal, that are the same 

kind.

Specimen An individual example of a species.

Tertiary The youngest Period of the Cenozoic Era, following the 

Cretaceous Period of the Mesozoic Era and occurring prior to the Quaternary 

Period of the Cenozoic Era.

Triassic Oldest Period of the Mesozoic Era; it spanned the time interval 

from 245 to 208 million years ago. The Triassic is named for the three 

different kinds of rocks of this age that occur in Germany, where the name 

"Triassic" was first used.
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References

Berry, W.B.N., 1968, Growth of a prehistoric time scale: W.H. Freeman and

Company, San Francisco, 158 p.

A thoroughly readable and interesting history of the development of 

the concept of geologic time. The revised edition (1987) is 

substantially revised and expanded.

Boardman, R.S., Cheetham, A.H., and Rowell, A.J., 1987, Fossil

Invertebrates: Blackwell Scientific Pub., Palo Alto, California, 713 p. 

This book is now considered by many to be the best textbook for 

college-level invertebrate paleontology courses. The information on 

evolution, biology, and ecology are all up-to-date. Many of the 

illustrations are black-and-white photographs. Compliments Moore, 

Lalicker, and Fischer (listed below).

Clarkson, E.N.K., 1979, Invertebrate palaeontology and evolution: George

Alien & Unwin, London, 323 p.

The text is easy to understand, even if it is a little dry. The real 

advantage to this book is that the illustrations are excellent. A third 

edition is now available.

Levi-Setti, Riccardo, 1975, Trilobites: A Photographic Atlas: University of

Chicago Press, Chicago, 213 p. (updated edition now available) 

This book is really a photographic atlas, meant for both the. 

professional scholar and amateur natural historian. It contains 

more than a hundred black-and-white photographs, illustrating the 

magnificent diversity within the trilobite group. There is also some 

information on the possible biology and ecology of trilobites.

McKerrow, W.S., ed., 1978, The ecology of fossils: an illustrated guide: The

MIT Press, Cambridge, Massachusetts, 384 p. (updated edition now

available)

One of the best books illustrating how fossils fit into their 

environments, and where those environments were located. 

Illustrated with numerous maps and block diagrams.

22
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References Continued

Moore, R.C., Lalicker, C.G., and Fischer, A.G., 1952, Invertebrate fossils:

McGraw-Hill Book Company, Inc., New York, 766 p. (out of print, but

occasionally available in used book stores)

For many years this was the textbook used in invertebrate 

paleontology courses at many colleges and universities. Although 

the information on the biology and ecology is somewhat dated, the 

book contains hundreds of illustrations that are still useful. 

Compliments Boardman, Cheetham, and Rowell (listed above).

Murray, J.W., ed., 1985, Atlas of invertebrate macrofossils: John Wiley &

Sons, New York, 241 p.

As the name implies, this book is meant to be used as a reference. It is 

probably the best source of photographs of fossils.

Ward, P.D., 1987, The natural history of nautilus: Alien and Unwin, Boston,

267 p.

A somewhat advanced text by an expert in the field of cephalopod 

biology and paleontology. It includes many useful and interesting 

photographs.

Ward, P.D., 1988, In search of nautilus: three centuries of scientific

adventures in the deep Pacific to capture a prehistoric Living Fossil: Simon

and Schuster, New York, 238 p.

More general in coverage than "The Natural History of Nautilus," this 

book tells more of the adventure of conducting scientific research 

in the waters of the southwestern Pacific Ocean.

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Additional Models

Alpha, Tau Rho, 1989, How to construct two paper 

models showing the effects of glacial ice on a 

mountain valley: U. S. Geological Survey Open-File 

Report 89-190 A&B (Available as a

3.5-in. MACINTOSH disk or a 30-p. report)

Alpha, Tau Rho, Lahr, John C., and Wagner, Linda F., 1989, 

How to construct a paper model showing the motion that 

occurred on the San Andreas fault during the Loma Prieta, 

California, earthquake of October 17,1989: U. S. 

Geological Survey Open-File Report 89-640A&B 

(Available as a 3.5-in. MACINTOSH disk or a 10-p. report)

Alpha, Tau Rho, and Lahr, John C., 1990, How to construct 

seven paper models that describe faulting of the Earth: 

U. S. Geological Survey Open-File Report 90-257 A&B 

(Available as a 3.5-in. MACINTOSH disk or a 40-p. 

report)

Alpha, Tau Rho, 1991, How to construct four paper models 

that describe island coral reefs: U. S. Geological Survey 

Open-File Report 91-131A&B (Available as a 3.5-in. 

MACINTOSH disk or a 19-p. report)

Alpha, Tau Rho, and Gordon, Leslie C., 1991, Make your 

own paper model of a volcano: U. S. Geological Survey 

Open-File Report 91-115A&B (Available as a 

3.5-in. MACINTOSH disk or a 4-p. report)

O
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Educator's Guide: /S 

Page 22 of 22_____ 

[Return to Table of Contents)

Additional Models Cont.

Alpha, Tau Rho, Page, Robert A., and Gordon, Leslie C., 1992, 

Earthquake effects, a computer animation and paper 

model: U. S. Geological Survey Open-File Report 

92-200A&B (Available as a 3.5-in. 

MACINTOSH disk or a 4-p. report)

Alpha, Tau Rho, Starratt, Scott W. and Chang, Cecily C., 1993, 

Make your own Earth and tectonic globes: U. S. Geological 

Survey Open-File Report 93-380A&B (Available as a 3.5- 

in. MACINTOSH disk or a 14-p. report)

Alpha, Tau Rho, and Stein, Ross S., 1994, Make your own paper 

model of the Northridge, California, earthquake, January

17,1994: U. S. Geological Survey Open-File Report 

94.143 4_p.

Alpha, Tau Rho, and Stein, Ross S., 1994, The Northridge, 

California, Earthquake of January 17,1994: A computer 

animation and paper model: U. S. Geological Survey Open-File 

Report 94-214 30-p.

To order these reports, contact:

USGS ESIC-Open-File Report Section 

Box 25286, MS 517 

Denver Federal Center 

Denver, CO 80225-0046

or call (303)-236-4476.

Print This Guide

Return to Table of Contents! <^J 25
Trilobite [Return to paper fossils!

Instructions J

Step 1 , Cut out trilobite's body, gills, and legs. 

Step 2, Glue gills to underside of

Step 3, Glue legs to underside 

of trilobite's gills.

trilobite's body.

Gills Glue to underside of body Legs Glue to gills

Step 4, Glue antennae to underside of head.

on the | reverse 

side
Step 1, Cut out trilobite's 

body, gills, legs, and antennae

Cut uJ2'r nw TO%:o!fcer^_ Cut 1

Cut Cut^

Antennae

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Cut

between

legs.

27
Step 2, Fold body. Fold 

Fold Fold 

Gills Legs

Cross section of trilobite.

28
Step 3, Fold gills, legs, and 

antennae. Fold

Body-O,

Gills ' Legs

Cross section of trilobita

29
Step 4, Glue body

ami antennae

Glue

Glue

Gills Legs

Cross section of trilobita

30
Step 5J Glue gills, legs, 

and antennae to body.

Gills ' Legs

Cross section of trilobita

31
Finished trilobite

32
Nautiloid [Return to paper fossils]

Instructions

Center Align to center line 

1 of shell

Location

of edge of 

shell j

®

\S X/

Step 1, Cut out head and shell 

of nautiloid.

she11 '

Step 3, Roll up and glue head 

and hyponome.

Step 4; Use the tvo tabs 

to glue head 

to inside 

of coiled 

shell.

Center J Align to center line of head

33
Step 1, Cut out shell 

and head. o 

o
Step 2, Roll and fold head.

35

Step 2, Roll anoldhead.

37
Step 3, Roll and fold shell.
Step 4, Glue head and shell

Glue Glue

39
Step 5, Glue head to shell
Finished nautiloid
( Return to Table of Contents

The End

Awesome wawF \ 

Dude!!

Diskette cover

Print diskette cover

TIAQ 

Make Tour Ovn Paper Fossils

Make Your Own 

Paper Fossils

by 

T.R.Alpih^ S.W.Starratt <ft J.W.Hendley

U.S. Geological Smvey 

Open-file Report 94-667