Park Paleontology 1

National Park Service

U.S. Department of the Interior

Park Paleontology

Geologic Resources Division, Paleontology Program

Volume 6, Number 2

Summer 2002

Table of Contents

National Park Service Welcomes Three

New Paleontologists ............................. 1

Fossil Walrus Skull Found on the Outer

Banks near Cape Hatteras ...................... 2

The Occurrence and Distribution of Fossil

Shells on U.S. mid-Atlantic Beaches .........3

California Dinosaur Tracks: Inventory

and Management .................................. 5

Can you identify the fossil ....................8

Recent Literature on Park Paleontology

Resources ............................................. 9

National Park Service

Welcomes Three New

Paleontologists

The ranks of paleontologists in the NPS has

been recently increased by three, bringing the

total number to 15.

Phil Gensler – Hagerman Fossil Beds

Phil was hired as Hagerman Fossil Beds National

Monument’s (HAFO) staff paleontologist in May

2002. Originally from northwestern Pennsylvania, Phil received a B.A. in Environmental Science with a Geology minor from Edinboro University of Pennsylvania in 1994. He then worked

as a County Technician at Crawford County

Conservation District issuing permits relating to

construction encroachments of wetlands, lakes,

and streams. In 1996 Phil started his graduate

work at Northern Arizona University, Flagstaff,

Arizona in the Quaternary Sciences Program. He

is completing his Masters and his thesis describes

the mid-Pleistocene vertebrate fauna from the

Coyote Badlands in Anza-Borrego Desert State

Park, California.

Phil has worked as a seasonal museum technician at HAFO during the 1998 and 1999 field

seasons and as a physical scientist from 2000 –

2001. Also, during 2001 he was acting Park

Paleontologist at HAFO. In addition to his work

in Anza-Borrego and at HAFO he has been

involved in Pliocene and Pleistocene-aged vertebrate paleontology projects throughout Arizona, Idaho, California, Nevada, and northern

Mexico.

Bill Parker - Petrified Forest

Bill is the new paleontologist at Petrified Forest

National Park. Born in New Haven, Connecticut

he completed his B.S. in Geology/Paleontology

at Northern Arizona University in 1999, and is

nearing completion of his M.S. in Geology, also

at Northern Arizona University.

Bill says that being able to do paleontology at

Petrified Forest National Park is a dream come

true since his main interests in the field are the

archosaurian reptiles of the Late Triassic. His

Master’s thesis involves the description of a new

skeleton of the aetosaur Desmatosuchus

haplocerus from Northern Arizona [editor’s

note, see Park Paleontology 6(1)]. Bill says, “I

guess that one could consider it fate that I

study aetosaurs. I was born in New Haven,

Connecticut and spent the first 6 years of my

life just “down the street” from a historical

quarry that produced the first aetosaur skeleton

known from the eastern United States.” His

interest in fossils was kindled by repeated visits

to the Yale Peabody Museum to see the dinosaurs when he was a kid and he is still in possession of his first (and only) self-authored dinosaur “book”, a ragtag assortment of several

drawings that he created and painstakingly

taped together when he was about 7 years old.

Unfortunately the first portion of his paleontological career came to an end as he “outgrew”

his dinosaur fever.

After high school Bill had no real interest in

attending college and instead went to work in

the hospitality industry. After several years of

managing kitchens in restaurants he felt the call

to return to school. At first torn between

archaeology and geology/paleontology he

decided to spend a summer doing each. In

1996 he spent two months in the country of

Belize excavating Maya sites on the western

border. He is probably one of the few vertebrate paleontologists whose first dig was of

Homo sapiens. Then in 1997 he spent two

weeks in the Hell Creek Formation excavating

Triceratops material and investigating a sizeable

hadrosaur bone bed. Needless to say, although

he greatly enjoyed both experiences, paleontology won out.

While searching for a senior thesis topic during

his undergraduate studies at Northern Arizona

University in 1998 his advisor mentioned a

partial reptile (aetosaur) skeleton from the

Chinle Formation of Arizona and thought it

would be great experience to excavate the

couple of bones and write up a description.

The few bones turned into over two hundred

with a relatively complete skeleton being

present and his senior thesis turned into a

Masters, along with a love for the late Triassic

Period. In May, 2001 Bill was hired by Petrified

Forest National Park to conduct a paleontological inventory of the park and he is still conducting surveys although in his present position the

duties have expanded. While at the park he has

excavated several significant specimens including another aetosaur skeleton, as well as several

partial phytosaurs.

Besides his Triassic work he has also worked in

the Late Cretaceous of Utah, doing a paleontological inventory for the Manti-LaSal National

Forest. His fieldwork and research has taken

him all over Arizona, Utah, New Mexico, Texas,

and even Mexico where he has done some

Pleistocene work. His future goals involve not

only finishing his work on the aetosaur but

eventually to pursue a Ph.D.

Matthew Smith – John Day Fossil Beds

Growing up surrounded by the fossil-rich waterways of North Florida, Matt developed an

early interest in the ancient and modern biota

of his home state. In 1992 he decided to

pursue a Zoology degree at the University of

Florida, Gainesville. Other than a brief foray

into the world of entomology with the Agriculture Department, he restricted his movements

as much as possible to the halls of the Florida

Museum of Natural History and the buildings

immediately adjacent. While lurking about he

discovered that the arcane field of fossil preparation was the only sensible avenue of study

within the greater world of Paleontology, being

that the preparation laboratory was where they

kept the coffee maker. After earning his Bachelors, he headed to the Smithsonian Institution

continued on page 2
2 Park Paleontology

in Washington DC to build supportive fiberglass

and plaster jackets for some of their oversized

fossils due to be shipped to their new facility

Maryland. In secret he kept close watch on the

masterful preparators employed there, and

dared to dream that he could one day apply

some of their techniques to fossils outside of a

crowded, metropolitan setting. He came close

to realizing this idle reverie when he traveled to

La Paz, Bolivia to assist the staff at el Museo

Nacional del Historie Natural in mounting the

skeleton of Eurygenium pacenium, a rather

unusual Notohippid. While there, he was also

lucky enough to go and work for a few short

days at the beautiful field locality of Salla, famous for some of the earliest primate fossils in

South America. Returning from Bolivia in May

of 1998, and at a loss for what to do next, he

applied for seasonal employment at John Day

Fossil Beds National Monument as a laboratory

technician. One thing led to another, and four

years latter he was offered a permanent position as a full time preparator. In this way his

musings while in Washington came full circle,

and he now works and resides in the wilds of

the beautiful John Day River Basin.

Three New NPS Paleontologists

Bill Parker excavating an aetosaur skeleton at

Petrified Forest National Park.

Fossil Walrus Skull Found

on the Outer Banks near

Cape Hatteras

Doug Stover

Cultural Resource Manger

Cape Hatteras National Seashore

Route 1, Box 675

Manteo, NC 27954-2708

In 1990, a park visitor to Cape Hatteras National Seashore came across an ancient walrus

skull washed up on the beach in Salvo, North

Carolina. National Park Service rangers acquired

the walrus skull and sent the specimen to the

Smithsonian Institution where it has been

analyzed and preserved since 1990. David

Bohaska, Museum Specialist at the Smithsonian

Institution has been studying the walrus skull,

and has determined that the skull is one of the

best specimens found. The walrus skull was

largely intact except for missing its two tusks.

The Walrus Skull has been returned to Cape

Hatteras National Seashore to be placed on

exhibit at the Graveyard of the Atlantic Museum, Hatteras, North Carolina.

The National Park Foundation has provided

funding to obtain a carbon 14 date on the

skull in order to try and determine its exact

age. The skull is currently at Stafford Research Laboratories in Boulder, Colorado

where a sample from the tusk is being removed for analysis.

Matt Smith in the lab at John Day Fossil Beds

puzzling over one of the latest finds.

Further Reading

Deméré, T. A. 1994. The Family Odobenidae, a

phylogenetic analysis of fossil and living taxa. In,

Berta, A. and T. A. Deméré (eds.), Contributions in

Marine Mammal Paleontology Honoring Frank C.

Whitmore, Jr. Proceedings of the San Diego Society

of Natural History 29: 99-123.

Fay, F.H., 1981. Walrus Odobenus rosmarus

(Linnaeus, 1758). pp. 1-23. In S.H. Ridgway and

R.J. Harrison, eds., Handbook of Marine Mammals.

Vol. 1. Academic Press, London.

Miller, R.F. 1997. New records and AMS radiocarbon dates on Quaternary walrus (Odobenus

rosmarus) from New Brunswick. Géographie

physique et Quaternaire 51(1): p. 1-5.

Riggs, S.R., W.J. Cleary and S.W. Snyder. 1995.

Influence of inherited geologic framework on

barrier shoreface morpholoy and dynamics.

Marine Geology 126:213-234.

Phil Gensler in the collections at Hagerman Fossil

Beds with a shell of a fossil turtle.

Right: View of the palate of the skull of fossil

walrus found at Cape Hatteras National

Seashore. Photo by: Doug Stover

A distinctive group of hoofed mammals

evolved in South America called the

notoungulates. They ranged in size from

small rabbit-like forms to the massive

Toxodon, which stood over 2 m high at the

shoulder. One group called the Notohippids

(meaning southern horse) has features of

the skull and incisors similar to that of

horses.

What is a Notohippid?
Park Paleontology 3

The Occurrence and

Distribution of Fossil Shells

on U.S. mid-Atlantic

Beaches

John F. Wehmiller

Department of Geology

University of Delaware

Newark DE 19716

[jwehm@udel.edu]

Linda L. York

U.S. National Park Service

Southeast Regional Office

100 Alabama St., S.W.

Atlanta, GA 30303

[Linda_York@nps.gov]

Many of the National Parks in the western

United States are known for their variety and

abundance of spectacular vertebrate and invertebrate fossils. In the past few years, however,

fossil discoveries of a more subtle nature have

been made on the beaches of the mid-Atlantic

coastal parks. In the National Seashores of the

East, calcium carbonate remnants of former

living organisms, transported and deposited on

the beaches over the past several thousand

years, reveal a part of the story of the dynamic

processes of coastal evolution reaching back

over the past several million years.

Mercenaria (commonly known as the Quahog

clam) is a robust mollusk found along the

Atlantic coast of the U.S. Though other shells

are part of this story too, they are typically more

fragile than Mercenaria and do not as readily

survive the coastal waves and weather. In this

brief article, therefore, Mercenaria specimens

collected from Cape Hatteras and Cape Lookout National Seashores will be used as examples

to explore questions about their geologic age,

their sources, and the geologic processes that

carried them from their source to the location

where they were found.

Where do we find these shells?

Coastal regions, particularly barrier islands and

beaches, are extremely dynamic geologic environments. During the past million years (the

last half of the Pleistocene epoch), an alternating fall and rise of sea level associated with

glacial cycles has occurred approximately ten

times (roughly every 100,000 years) as major

northern hemisphere ice sheets have expanded

and contracted. Approximately 18,000 years

ago, when ice sheets were at their maximum

volume, global sea level was at a low point of

about 120 meters below the current level, and

coastal landforms were far from their present

locations. Subsequent deglaciation caused a

global rise in sea level, causing a transgression

of the shoreline upward and landward across

the continental shelf, eventually (within the past

5,000 years) reaching the modern shoreline

position.

Each interglacial high stand (period of ice sheet

retreat) creates a variety of sedimentary deposits associated with estuary, marsh, lagoon,

beach, and continental shelf environments.

Subsequent glacial/interglacial sea level regressions and transgressions modify these preexisting deposits through erosion and/or further

sediment accumulation. Shells are part of this

migration. Although only a small fraction may

be preserved during their long history as fossils,

some of these shells are transported and deposited (often by storms) on beaches, often in

overwash deposits behind coastal dunes. Later,

as the beaches migrate inland, some of these

shells become exposed and/or re-deposited on

the modern beach. Depending on its durability,

fossil material incorporated into the original

sedimentary unit (the source unit) may be

exposed, transported, and re-deposited in a

younger unit.

Figure 1. Map of the U.S. Atlantic Coast from Cape Henry (VA.) to Cape Fear (NC). Sampling of beaches for

fossil material has occurred along the entire section of coast indicated by the coast-parallel lines. The heavy

red line indicates the position of the schematic cross section shown in Figure 4.

Figure 2. Cape Hatteras Mercenaria shells with D/L data. Shells collected approximately 5 km southwest

of Cape Hatteras Lighthouse in January 1993, at Cape Point. Specimen D is approximately 7,500 years old

based on a radiocarbon date; note matrix of cemented shell debris on specimen F - this matrix is common in

rock fragments found on NC beaches. Specimen A: D/L = 0.37; Specimen B: D/L = 0.25; Specimen C: D/L =

0.31; Specimen D: D/L = 0.16; Specimen E: D/L = 0.46; Specimen F: D/L = 0.30.

continued on page 4
4 Park Paleontology

What do these fossils look like?

To better understand this concept of coastal

evolution, shells collected on the Outer Banks of

North Carolina, in Cape Hatteras and Cape

Lookout National Seashores have been studied

(Figure 1). Most of the shells collected are not

particularly unusual in appearance, though

some have a gray-blue, darkened coloration,

possibly the result of being buried in the mud

for hundreds of thousands of years. Because

fossil and modern shells are frequently similar

in appearance, over the past decade, geologic

dating methods have been used to determine

the frequency of occurrence of fossil shell

material on mid-Atlantic beaches, specifically

those that have not been affected by artificial

beach nourishment (Wehmiller et al, 1995.)

How old are these shells, and how do we

determine their age?

The principal method employed to determine

the geologic ages of these shells is amino acid

racemization (AAR). This method relies upon

the time-dependent alteration of proteins and

their constituent amino acids preserved in the

shell hard part. Natural amino acids exist in

two geometric forms referred to as “lefthanded” (L for “levo”) and “right-handed” (D

for “dextro”). Most living systems utilize only

the left-handed amino acid. But over time, the

left-handed form racemizes to create the righthanded form. As a result of this process, the

ratio of right to left (D/L) grows from zero to

1.0 (an equal abundance of the two forms in

equilibrium).

The rate of this reaction is dependent on temperature, so the “clock” is not an absolute one.

However, the rate can be calibrated with independent dating methods (particularly radiocarbon – or Carbon-14) for a given region where

temperatures are similar. In the climate of the

mid-Atlantic region of the eastern U.S., the

reaction takes at least one million years to reach

equilibrium. Because the upper limit of radiocarbon dating is about 40,000 years, AAR age

estimates can be made over a much greater

time range than can be dated by radiocarbon.

AAR is also an economical and rapid analytic

method, hence it can be applied to a far larger

number of samples than methods based on

radioactivity.

Examples of the collections Mercenaria specimens from Cape Point (Cape Hatteras) and

South Core Banks are shown in Figures 2 and

3. Each analysis used a fragment from either

the hinge or central portion of the shell as

indicated. The D/L ratios (for one amino acid

known as isoleucine) for each shell are given in

the captions. All but specimen J (Figure 2) are

from the Pleistocene era (greater than about

12,000 years in age) based on the measured

values of the D/L ratio. The one shell that is not

Pleistocene (specimen J) is about 7,500 years in

age, based on a radiocarbon analysis of this

shell. The ratios for the older shells cluster into

three groups with the following ranges: 0.24-

0.31; 0.37-0.46; 0.65-0.70.

Figure 4 shows a representative geologic cross

section for eastern North Carolina, with superposed layers representing the successively older

coastal units that accumulated during Pleistocene sea level transgressions. These units are

recognized in onshore drilled sections, and they

are exposed on the inner continental shelf and

shoreface of the modern barrier islands. Sedimentary units found in the onshore subsurface

have the same D/L ratios as those found in

beach specimens, indicating that these beach

shells have been derived from correlative units

that are being actively exposed and eroded by

modern coastal processes.

How old are these Pleistocene shells?

This question can be answered by using models

for the rates of amino acid racemization and/or

estimated ages for selected onshore samples.

Using this approach, the three clusters of D/L

values summarized above represent ages of

approximately 100,000, 300,000, and 700,000

years, respectively. These age estimates have

Figure 3. Core Banks shells, collected April, 1993, due east of Davis NC. Specimen G: D/L = 0.24; Specimen H: D/L = 0.70;

Specimen I: D/L = 0.27; Specimen J: D/L = 0.30; Specimen K: D/L = 0.24; Specimen L: D/L = 0.65

Figure 4. Representative geologic cross section of the N. C. coastal plain, showing D/L values obtained in

subsurface onshore sections and in shells collected on the barrier island beaches. See Riggs et al. (1992) for

background information on the onshore geology.

continued on page 5
Park Paleontology 5

California Dinosaur

Tracks: Inventory and

Management

Robert E. Reynolds

LSA Associates, Inc.

1650 Spruce Street

Riverside, California 92507

Ted Weasma

Mojave National Preserve

222 East Main Street

Barstow, California 92311

California’s only dinosaur tracks are Middle

Jurassic in age and are located in the Aztec

Sandstone in the eastern Mojave Desert near

Mojave National Preserve. The Aztec crops out

in the Mojave Block at Ord Mountain, the Soda

Mountains, Cow Hole Mountains and in the

Mescal Range.

The popularity of dinosaurs during the late 20th

century prompted concern that no detailed

inventory existed for California’s only tracks.

Not only are the tracks unique to the state, but

early Jurassic track sites are rare in the western

United States. Previous work identified

trackways representing three bipedal

coelurosaurs assigned to the ichnogenera

Anchisauripus, Grallator, and an unnamed

ichnogenus. In addition to the coeleurosaur

tracks, tracks and trackways of more than 4

quadrupedal ichnogenera are represented. The

track impressions of both quadrupeds and

bipeds produce compression rings that suggest

original slope of dune topography. Also preserved are sedimentary structures, cross-bedding, ripples, raindrops and trails and tracks left

by invertebrates.

quite large uncertainties for a variety of reasons,

but they suggest that some beach shells that

may otherwise appear quite “well-preserved”

are, in fact, several hundred thousand years in

age.

How long has it been since they were

eroded from their host unit and deposited

at their present location?

The answer to this question must consider

several factors: the history of sea-level rise over

the past few thousand years, the depth below

present sea level of the source units, the transport distance that can be “survived” by these

shells, and the very mechanisms by which these

large shells are moved from submerged to

emergent locations. These factors depend on

storm events, rates of barrier island migration

(in response to sea-level rise), the supply of

sediment (sand) in the coastal system, and the

geologic framework that underlies the barrier

islands (Riggs et al., 1995). A large abundance

of nearly complete Pleistocene shells indicates

limited exposure to processes of fragmentation,

suggesting proximity to source units. The ratio

of fragmented to whole fossil shells varies

widely along the Outer Banks, and it is remarkably low at Cape Point, suggesting that this

area is an “island” of older sediments

(Wehmiller et al., 1995).

The shells shown in Figures 2 and 3 are typical

of the Pleistocene fossil shells found along the

mid-Atlantic beaches of the US. The frequency

of occurrence of these shells is controlled by a

large number of factors, including the actual

extent of the preserved record of Pleistocene

sea levels in a given region, the extent to which

these older records are “hidden” from modern

coastal erosion by overlying sandy deposits, and

the shell content of the older units. Based on

information obtained at sites from New Jersey

to northern Florida, the NC Outer Banks appear

to offer the greatest concentration of these

Pleistocene fossils.

What story is told by the fossil shells found

in the Cape Hatteras and Cape Lookout

National Seashores?

Although it may be difficult to use the ages of

beach shells to identify the specific sources of

these samples, beach samples do provide an

integrated record of the geology of the coastal

region. Beach sampling suggests where host

units might be found on the continental shelf.

Where large concentrations of fossils are found,

it often indicates that older units are exposed

on the nearby shelf, further suggesting an area

vulnerable to erosion. More complicated and

expensive sampling techniques (drilling and

coring) on the continental shelf provide a more

detailed record confirming these conclusions.

So even though the beach fossils may not be

very unusual or striking in their appearance,

they are a component of the continuing story

of the evolution of coastal landforms that

change on timescales of years to millennia.

Further Reading

Riggs, S. R., L. L. York, J. F. Wehmiller, and S. W.

Snyder, 1992, Depositional patterns resulting from

high frequency Quaternary sea-level fluctuations in

northeastern North Carolina. In: C. H. Fletcher III

and J. F. Wehmiller (editors), Quaternary Coasts of

the United States: Marine and Lacustrine Systems.

Tulsa, SEPM (Society for Sedimentary Geology)

Special Publication No. 48, pp. 141-153.

Riggs, S. R., Cleary, W. J., and Snyder, S. W., 1995,

Influence of inherited geologic framework on

barrier shoreface morphology and dynamics. Marine Geology 126, 213-234.

Wehmiller, J.F., York, L. L., and Bart , M. L. , 1995,

Amino acid racemization geochronology of reworked Quaternary mollusks on US Atlantic coast

beaches: implications for chronostratigraphy,

taphonomy, and coastal sediment transport. Marine Geology 124, 303-337.

See also: http://

www.geology.udel.edu/wehmiller/

shells.html

Acknowledgments:

Support from the U.S. National Science Foundation, the U. S. Geological Survey, and the U. S.

National Park Service is gratefully acknowledged, as are the discussions with many collaborators in discussions or field collections,

particularly P. L. Wehmiller, K. and R. Thieler,

and S. Riggs.

Documenting outcrops of Middle Jurassic Aztec Sandstone with dinosaur tracks.

continued on page 6
6 Park Paleontology

Dinosaur tracks in the Azrec Sandstone.

One hundred and sixteen track and structure localities were recorded, including outcrop panels

and loose slabs. Of importance, the second of

two occurrences of a small (juvenile) bipedal

trackway paralleling an adult trackway was located. All track locations were photographed

and attitudes were taken of outcrops that reflected the local dune surface. Baseline data is

now available for further inventory and management of the trackway site. Research questions

that can now be addressed include, what are the

characteristics of the sedimentary facies in which

tracks are preserved, and where they are not preserved; and whether there is any biological or

geographic significance to the direction of the

tracks. This baseline data will help quantify research questions and help managers with further

inventory and the appropriate management of

the trackway sites.

Evans (1958) first recognized the tracks in the

Aztec Sandstone of California. Descriptions of the

three bipedal and four quadrupedal tracks were

published by Reynolds (1989), who documented

the direction of travel for the quadruped tracks

and demonstrated that the bipeds had less directional preference. Review of Jurassic tracks in

Utah and Wyoming (Kvale et al., 2001;

Breithaupt et al., 2001) as well as field investigations in the Aztec of southern Nevada suggest

that the ichnogenera and ichnospecies represented in the Mescal Range section are uncommon west of the Rocky Mountains.

The age of the Aztec Sandstone in the Mescal and

Goodsprings Ranges was originally referred to the

Jurassic (Hewett, 1956; Evans, 1958) but its exact

position within the Jurassic has been questioned.

The first tentative dates on the Delfont Volcanics

that overlie the Aztec in the Mescal Range were in

the 150 Ma range, and two of the dinosaurian

ichnogenera found in the formation were

previously known from the Newark Supergroup of the Connecticut Valley which spans

the Triassic and the Jurassic. Recent work on

andesite interbedded with the Aztec in the

Cowhole sequence gave a date of 173 ± 4

million years and a date on the basal ignimbrite that overlies the sequence has permitted

more accurate placement of the age of the

formation at 170 ± 2 million years.

Based on the dates from the Cowhole section

the age of the dinosaurian trackways would

be middle Jurassic, and based on the stratigraphic relationships in the Mescal Range, no

younger than mid-Cretaceous. A middle

Jurassic age accords well with the relationship

of two ichnogenera, Anchisauripus, and

Grallator, to the tracks in the Jurassic portion

of the Newark Supergroup as well as in the

Moenave Formation of northeastern Arizona

(Irby, 1993). The unnamed ichnogenus from

the Mescal Range is smaller than tracks with

similar morphology from the lower Cretaceous of South Dakota (Anderson, 1939) and

the Jurassic of China (Zhen et al., 1986), and

presumably indicates a pre-Cretaceous age.

Some or the research questions being pursued include:

-Do the tracks reflect the population

dynamics of each ichnogenera?

-How do the dynamics of quadrupedal

ichnogenera relate to those dynamics

of the bipeds.

-How do the dynamics of all

ichnogenera relate to the specific substrate; what were they doing as they

crossed dune sand; can feeding habits be

speculated upon?

-The size of the foot imprint varies both

with age of individual and with consistency of substrate. Can parameters for

variation by age be distinguished from

differentiation due to substrate?

-Further work on direction and bearing of

bipedal and quadrupedal track makers.

Data can be corrected to adjust for anticlinal folding.

-Tracks apparently are best or only preserved in certain sandstone lithologies.

Can environmental parameters be applied

to those lithologies?

-Track bearing horizons can now be

measured to the lowest overlying

volcaniclastic unit. If this unit can be

dated, it will provide time constraints on

the local ichnogenera.

-Population diversity may be studied by

detailed measurements of the print size of

the large sample of one ichnogenus.

Summary

Recently acquired UTM coordinates record 116

tracks, trackways or structures in the Aztec

Sandstone of the Mescal Range in the eastern

Mojave Desert. The 2001 inventory identified

loose slabs or outcrops containing 44 panels

with bipedal coeleurosaur tracks, 73 panels

with quadruped tracks, 19 panels with invertebrate tracks, and five localities where sedimentary structures were recorded. Plots of the loci

suggest that tracks occur in two arenaceous

facies of the Aztec Sandstone. Among the more

interesting discoveries during the survey was a

new panel that contained small and large tracks

of the unnamed ichnogenus walking in parallel

directions.

The inventory of the Mescal Range tracks provided critical base line data for management

and demonstrates the need for further inventory and research in the Aztec Sandstone.

The detailed location data allows resource

managers to determine if sandstone blocks

and outcrops are subject to movement,

degradation or removal. The photographic

record will indicate whether outcrops and

individual tracks are subject to degradation

 by weather or vandalism. Further surveys are

needed as other outcrops remain to be examined for track impressions and the existing

data only describes sets of conditions where

track preservation is most likely to exist. Annual

review of changes to California’s only dinosaur

track site will determine if the current level of

resource management is adequate for their

long-term preservation for scientific study,

education, and interpretation.
Park Paleontology 7

Ted Weasma of Mojave National Preserve with a GPS unit used for documenting the location of the

dinosaur tracks in the Aztec Sandstone.

References

Anderson, S.M. 1939. Dinosaur tracks in the

Lakota Sandstone of the Eastern Black Hills,

South Dakota. Journal of Paleontology 13(3):361-

364.

Beckerman, G.M., J.P. Robinson, and J.L. Anderson. 1982. The Teutonia Batholith pp. 205-220

in E.G. Frost and D.L. Martin (eds.). MesozoicCenozoic Tectonic Evolution of the Colorado

River Region, California, Arizona, and Nevada.

Cordilleran Publishers, Geological Society of

America Field Trip.

Breithaupt, B.H., E.H. Southwell, T.L. Adams and

N.A. Matthews. 2001. Innovative documentation

methodologies in the study of the most extensive

dinosaur tracksite in Wyoming. Pp. 113-122 in V.L.

Santucci and L. McClelland (eds.). Proceedings of

the 6th Fossil Resource Conference. Technical

Report NPS/GRD/GRDTR-01/01.

Evans, J.R. 1958. Geology and mineral deposits of

the Mescal Range quadrangle, San Bernardino

County, California. Scale 1:24,000, University of

Southern California, Unpublished Masters Thesis.

Fleck, R.J., M.D. Carr, G.A. Davis and C.B.

Burchfiel. 1994. Isotopic complexities of the

Delfont Volcanic Rocks, eastern Mescal Range,

southeastern California. Stratigraphic and tectonic

implications. Geological Society of

America Bulletin 106:1242-1253.

Fleck, R.J. and R. E. Reynolds. 1996. Mesozoic

stratigraphic units of the eastern Mescal Range,

southeastern California. San Bernardino County

Museum Association Quarterly 43(1):49-54.

Hewett, D.F. 1956. Geology and mineral resources of the Ivanpah Quadrangle, California

and Nevada. United States Geological Survey

Professional paper 275: 172 pp.

Irby, G.V. 1993. Early Jurassic dinosaur track

sites, northeastern Arizona. pp. 15 - 23 in D.

Boas and M. Dornan (eds.). First Annual Symposium, Fossils in Arizona. Mesa Southwest Museum.

Kvale, E.P., G.D. Johnson, D.L. Mickelson, K.

Keller, L.C. Furer, and A.W. Archer. 2001.

Middle Jurassic (Bajocian and Bathonian) dinosaur

megatracksites, Bighorn Basin, Wyoming, USA.

Palaios 16:233-254.

Reynolds, R.E. 1989. Dinosaur trackways in the

lower Jurassic Aztec Sandstone of California. Pp.

298-292 in D.D. Gillette and M.G. Lockley (eds.).

Dinosaur Tracks and Traces. Cambridge University

Press.

Zhen, S., J. Li, and C. Rao. 1986. Dinosaur

footprints of Jinning, Yunnan. Memoirs of the

Beijing Natural History Museum 33: 18 pp.

What Are Trace Fossils?

Fossils can be divided into two general groups – body

fossils and trace fossils. Body fossils are the preserved anatomical parts

of the plant or animal and provide direct evidence while trace fossils are

produced by the animal’s activities. A trace fossil is therefore indirect

evidence of ancient life and provides information on the behavior of the

organism. There are many different types of trace fossils. Dinosaur

tracks and trackways are perhaps the best known. Often animal’s burrows become filled with sediments and are preserved. Nest structures

are another type of trace fossil. Evidence of feeding can be preserved as

trace fossils such as insect chewing on leaves. Tooth marks on bones

may be left by a predator while feeding on its prey or by rodents chewing on bones for the minerals. Other examples of trace fossils are

borings. These may be into shells by marine organisms or may be made

by insects in wood. Some insects like dermestid beetles can bore into

bone. Eggs, gizzard stones, and dung are also considered trace fossils.

The study of trace fossils is called ichnology.
8 Park Paleontology

 CAN YOU IDENTIFY THE FOSSIL?

 Name the fossil and the park where it is found.

Answer on page 9

Dung of the extinct ground sloth, Nothrotheriops

shastensis, from Rampart Cave, Grand Canyon

National Park, Arizona.

The worldís largest concentration of

caves (4) containing fossil ground sloth

dung occurs in Guadalupe Mountains

National Park.

The second largest number of caves

with fossil ground sloth dung occurs in

Grand Canyon National Park.

DID YOU KNOW?
Park Paleontology 9

Skeleton of the Hagerman Horse, Equus simplicidens, from the Smithsonian Horse Quarry, Hagerman

Fossil Beds National Monument.

Recent Literature on Park Paleontology Resources

Chapters

1. Magic Mirror (geology and geography of

Snake River Plain)

2. Equus Evolves (fossils and paleontology)

3. Arrows and Atlatls (archeology)

4. First Encounters (fur trade and exploration)

5. Devil’s Backbone (Oregon Trail and emigration)

6. Staking Claim (ranching, farming, and

mining)

7. Skull in the Quarry (fossil discovery and

monument history)

8. Route 30 (roadside culture and landscape)

9. Making Magic (river ecology)

Includes bibliographical references and index.

Photographs, Maps, Charts, Paintings, Illustrations

Price $29.95

Equus Evolves: The Story of the

Hagerman Horse

In addition to the Secrets book, Black Canyon

Communications and the Hagerman Fossil

Council are also pleased to announce the

publication of Equus Evolves: The Story of

the Hagerman Horse. This book excerpts

two chapters from the Secrets book along

with two additional chapters that focus exclusively on the Hagerman Horse and the

Hagerman Fossil Beds National Monument.

The story sheds light on the fossil finds in

Hagerman and how a natural wonder became a national monument.

Secrets of the Magic Valley and

Hagerman’s Remarkable Horse

Black Canyon Communications in cooperation

with Hagerman Fossils Beds National Monument, the Hagerman Fossil Council and Boise

State University is pleased to announce the

publication of Secrets of the Magic Valley

and Hagerman’s Remarkable Horse. Edited

by Boise State History professor Todd Shallat,

the fully illustrated book tells the story of

Idaho’s Magic Valley, from the prehistoric Ice

Age mammals to emigrants on the Oregon

Trail to the complex harnessing of water that

transformed a desert into an important agricultural region. But the story does not always

match the myths and legends: “Humans alter

nature, but nature bites back in a continuous

process that results in a mythic landscape

both human and natural with surprising secrets and unexpected twists” (p. 20).

In addition to telling the story through words,

the book tells the story through hundreds of

historic and contemporary photographs as

well illustrations, maps, and paintings.

Answer to Fossil Identification from

page 8

It is part of a burrow of the extinct beaver

Palaeocastor foun d at Agate Foss il Beds

National Monument, Nebraska

Chapters

1. Living Rock (geology)

2. Equus Evolves (fossils and paleontology)

3. Skull in the Quarry (fossil discovery and

monument history)

4. A Future Tied to the Past (future of

research and development of the monument)

Includes bibliographical references and index.

Photographs, Maps, Charts, Paintings, Illustrations

Price $12.50

Both publications are available from

Hagerman Fossil Beds National Monument,

P.O. Box 570, Hagerman, Idaho 83332
10 Park Paleontology

EXPERIENCE YOUR AMERICATM

Park Paleontology is published intermittently

each year by the Geologic Resources Division. It

is available as a PDF file on the Internet at

http:www2.nature.nps.gov/grd/geology/paleo/

news/newsletter.htm

Copies may be printed from the internet for free

distribution.

Editor

Greg McDonald

Associate Editor

Christina Von Stroh

Contributors

Robert E. Reynolds

Doug Stover

Ted Weasma

John F. Wehmiller

Linda L. York

Comments? Write to:

Greg McDonald

Geologic Resources Division

National Park Service

P.O. Box 25287

Denver, Colorado 80225

National Park Service

U.S. Department of the Interior

Natural Resource Program Center

Geologic Resources Division

Paleontology Program

P.O. Box 25287

Denver, Colorado 80225

303 969-2821

First Class Mail

Postage and Fees

P A I D

Denver, CO

G-83

Flower of the plant, Florissantia, named for Florissant, CO, home

of Florissant Fossil Beds National Monument.