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A SET-UP FOR RAPID SCREEN-WASHING UNCONSOLIDATED SEDIMENTS FOR SALVAGE-COLLECTING LARGE VERTEBRATE FOSSILS (PIPE CREEK SINKHOLE, LATE NEOGENE, GRANT COUNTY, INDIANA, USA)

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Constraints of time, personnel, and financial resources made it necessary to devise a system for rapid, salvage screen-washing of a heterogeneous mixture of unconsolidated fossiliferous sediments and intermixed, unrelated sediments from a Neogene continental sinkhole site in northern Indiana, USA. We constructed three sets of an apparatus that used a tractor to load large quantities of sediment into a soaking trough, after which the sediment was rapidly passed through coarse screens using power hoses. This setup allowed recovery in a timely manner of large-vertebrate fossils from a large volume of mixed sediments that otherwise might never have been collected.
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2020. Proceedings of the Indiana Academy of Science 129(2):88–96
A SET-UP FOR RAPID SCREEN-WASHING UNCONSOLIDATED
SEDIMENTS FOR SALVAGE-COLLECTING LARGE VERTEBRATE
FOSSILS (PIPE CREEK SINKHOLE, LATE NEOGENE, GRANT
COUNTY, INDIANA, USA)
James O. Farlow
1,2
: Department of Biology, Indiana-Purdue University, 2101 East
Coliseum Boulevard, Fort Wayne, IN 46850 USA
Ronald L. Richards
3
and Brian D. Johnson: Indiana State Museum and Historic Sites,
Indianapolis, IN 46204 USA
Peter L. Falkingham: School of Natural Sciences and Psychology, Liverpool John Moores
University, England
ABSTRACT. Constraints of time, personnel, and financial resources made it necessary to devise a system
for rapid, salvage screen-washing of a heterogeneous mixture of unconsolidated fossiliferous sediments and
intermixed, unrelated sediments from a Neogene continental sinkhole site in northern Indiana, USA. We
constructed three sets of an apparatus that used a tractor to load large quantities of sediment into a soaking
trough, after which the sediment was rapidly passed through coarse screens using power hoses. This set-up
allowed recovery in a timely manner of large-vertebrate fossils from a large volume of mixed sediments that
otherwise might never have been collected.
Keywords: Screen-washing, fossil vertebrates, Pipe Creek Sinkhole
INTRODUCTION
Although abundant and diverse Neogene (late
Tertiary) continental fossil vertebrate assemblag-
es have long been known from western and
coastal areas of North America (Janis et al. 1998,
2008), until recently they were unknown from the
interior of the eastern half of the continent. This
situation changed with discovery of the Mio-
Pliocene (late Hemphillian or early Blancan, ca. 5
million-year-old) Pipe Creek Sinkhole (PCS) site
in Grant County, Indiana (Farlow et al. 2001),
and shortly afterward the Gray Fossil Site of
about the same age from Tennessee (Schubert &
Mead 2011). Because these are the only two sites
presently known from the Central East paleobio-
geographic region of North America (Janis et al.
1998, 2008), they are of particular interest for
reconstructing the paleoecology (Swinehart &
Farlow 2020), paleoclimate (Shunk et al. 2009;
Ochoa et al. 2016), and biogeography, and even
the geomorphological history (Sunderman et al.
2010; Fleming et al. 2018), of North America
during the late Neogene.
The fossiliferous Neogene sediments of PCS
have had a rather checkered history. The sinkhole
developed in the limestone flank beds (Wabash
Formation) of a Silurian reef (Lehman & Simo,
1989, 2000; Sunderman et al. 2010; Fleming et al.
2018). At least once the sinkhole became plugged
to form a pond and/or wetland, in which the late
Neogene fossiliferous deposit accumulated (Far-
low et al. 2010b; Sunderman et al. 2010). This
deposit was itself later buried beneath glacial till.
Quarrying operations by Irving Materials, Inc.
(IMI) at their Pipe Creek Jr. quarry stripped away
most of the sinkhole’s sediments. The unconsol-
idated sediments (including a substantial part of
the fossiliferous deposit) removed from the
sinkhole were dumped in a Spoil Pile at the side
of the quarry. In 1998 a joint operation of the
Indiana State Museum (INSM; the ultimate
repository of most of the PCS fossil collection)
and Indiana-Purdue University Fort Wayne
1
Corresponding author: James O. Farlow, 260-481-
6254 (phone), farlow@pfw.edu.
2
Allsupplementalmaterialcanbeaccessedby
clicking on the ‘‘Supplemental Materials’’ Link on
the IAS Proceedings page (https://www.
indianaacademyofscience.org/publications/
proceedings).
3
Ronald L. Richards passed away while the
manuscript was in press. See note in the acknowl-
edgments.
88
(IPFW; now Purdue University Fort Wayne)
screen-washed a portion of the Spoil Pile,
allowing recovery of several very good vertebrate
fossils (Farlow et al. 2001; Martin et al. 2002;
Dawson et al. 2008; Czaplewski et al. 2012;
Prothero & Sheets 2013; Martin 2014; Goodwin
& Farlow 2019), but leaving a great deal of Spoil
Pile material unprocessed. After 1998 IMI quar-
rymen dumped a layer of unrelated sediment over
the Spoil Pile. Although we initially viewed this in
dismay, thinking that it would make access to
fossils in the Spoil Pile more difficult, the event
turned out to be fortuitous, because it to some
extent protected the Spoil Pile until we could
secure funds to resume work on this material.
When our most intensive field work began in
2003, we thought that only a small amount of
undisturbed, in situ fossiliferous sediment re-
mained in the sinkhole itself. The plan was to
document and process this material quickly, and
then resume processing the Spoil Pile. To our
surprise and delight, a considerable amount of in
situ sediment was still present, and so we spent the
field seasons of 2003–2006 processing it. Fortu-
nately, enough intact sediment remained in situ in
the sinkhole to allow reconstruction of the site’s
history (Farlow et al. 2010b; Sunderman et al.
2010). Because our work was focused on the in
situ sediment, we never had the time or resources
to resume work on the Spoil Pile during those
years.
Screening procedures followed protocols pre-
viously developed by Richards for processing
fossiliferous Pleistocene deposits (Richards 1972,
1980, 1982, 1983, 1985, 1986, 1987, 1990, 1994a, b,
2007; Holman & Richards 1981; Richards &
McDonald 1991; Swinehart et al. 2005; Whitaker
& Richards 2005). The fossiliferous deposit was
mainly a ca. 2-m thick, unconsolidated clay
(Argast & Farlow 2010; Zones A and B of Farlow
et al. 2010b), which after soaking readily passed
through screens; we found it unnecessary to dry
the sediment prior to screening, as is commonly
done in collecting microvertebrate fossils (e.g.
McKenna et al. 1994; Cifelli 1996). In routine on-
site screen washing prior to 2011, sediment was
passed through two stacked screens, an upper
6.35-mm (¼-in) mesh coarse screen, and a lower
1.2-mm mesh.
Concentrate from both fractions was then
picked both on and off-site. This yielded literally
thousands, possibly tens of thousands, of individ-
ual bones, pieces of wood and other Neogene
plant and animal fossils (Farlow & Argast 2006;
Dawson et al. 2008; Farlow et al. 2010a, b;
Czaplewski et al. 2012; Prothero & Sheets 2013;
Martin 2014; Ochoa et al. 2016; Fleming et al.
2018; Goodwin & Farlow 2019; Swinehart &
Farlow 2020). Beneath the fossiliferous deposit
was a much thicker unit of red clay that was
devoid of fossils (Zone C of Farlow et al. 2010b;
also see Argast & Farlow 2010).
In addition to a diversity of both wetland and
dryland plants (Farlow et al. 2001; Shunk et al.
2009; Ochoa et al. 2016), PCS preserves a
remarkably diverse vertebrate assemblage for its
size; the PCS pond and/or wetland was about 19
m39.5 m (but may not have been continuous
over that area at any one time). In terms of the
relative abundance of vertebrate specimens, PCS
is mainly a microvertebrate site (Eberth et al.
2007; Farlow et al. 2010b), with many taxa of
small animals, but overwhelmingly dominated by
ranid frogs. Other PCS microvertebrates include
fishes, salamanders, toads, snakes, turtles, tor-
toises, small mammals, and scrappy, fragmentary
birds. After several years of picking microfaunal
remains from many tons of processed sediment,
we are confident that we have recovered a
representative and comprehensive sample of the
PCS microfauna, further study of which is on-
going.
The medium-sized to large-mammal assem-
blage is moderately diverse. The faunal list
includes a beaver (Dipoides), skunk (Buisnictis),
three canids (a fox, a coyote-sized form, and a
bone-crushing borophagine [Borophagus or pos-
sibly Epicyon; cf. Wang et al. 1999]), a lynx (Felis
cf. F. rexroadensis), a bear (Plionarctos), two
peccaries (Platygonus and Catagonus), three
camelids (Megatylopus,Titanotylopus,andHemi-
auchenia), a deer or deer-like ungulate, and the
stumpy-legged rhinoceros Teleoceras.Forthe
most part, large vertebrate specimens occurred
as isolated bones, at least in the in situ sediments
(the degree of articulation or association obvi-
ously could not be determined for specimens from
the Spoil Pile). Although prior to 2014 we had
good dental material for some of these bigger
animals, for others all we had were postcranial
bones, which mostly did not allow firm identifi-
cation. Consequently the main goal for our
further work was to find more material—partic-
ularly cheek teeth—that would permit firmer
identifications. We also sought to improve
sampling of the large-mammal diversity from
the sinkhole fossiliferous sediments.
FARLOW ET AL.—RAPID SCREEN-WASHING FOR LARGE FOSSILS 89
By 2006 all of the remaining in situ fossiliferous
sediment had been removed from the sinkhole.
Over the following years IMI geologist Jon
Havens and INSM volunteer Victor Porter
periodically examined the Spoil Pile for remains
newly exposed by weathering, finding a particular
spot of mixed sediment where larger bone
fragments were recovered. This was brought to
the attention of IMI, and they scooped up its
fossiliferous sediment and red clay, and the
sediments covering it, and piled the now inter-
mixed unconsolidated material in a location well
away from the main quarry operations. A
company representative estimated that the total
volume of translocated sediment was 31–38 m
3
(40–50 yd
3
).
When work began on this material in 2011, we
thought we could process all of the translocated
Spoil Pile in a single week of work. We began
screening with a combination of 6.35-mm (1/4-in)
and 1.2-mm mesh screens; but progress became
slow, with so few fossils being recovered that we
shifted to using only 6.35-mm mesh on two of our
screening stations and a third screening station
with 12.7-mm (½-in) mesh. Sediment was driven
through the screens using 38.1-mm (1.5-in)
diameter firehoses with spray nozzles. At the end
of the week, however, it was clear that once again
we had underestimated the amount of sediment.
To process all of the remaining material in a
reasonable amount of time, we would have to
rethink the scale and speed of our operations.
In 2012 we were galvanized when a canid
dentary bearing cheek teeth was found lying on
top of the Spoil Pile (Fig. 1). This proved that
there was still good fossil material to be discovered
in those sediments, so we obtained funds for
another field season.
2014 ON-SITE SCREENING
PROCEDURES
The problem.—In planning for the 2014 field
season, several constraints needed to be ad-
dressed. It had become apparent during our
week’s work in 2011 that the proportion of
fossiliferous sediment was now only a minor
fraction of the total translocated Spoil Pile. The
bulk of the Spoil Pile as it then existed was
unfossiliferous red clay from the sinkhole
deposit, along with substantial amounts of
unrelated sediment that had been dumped onto
the Spoil Pile at its previous location. Worse,
the fossiliferous sediment, red clay, and extra-
neous sediment were all now thoroughly
intermixed. Processing all of this material
through the screens used in 2011 had been
extremely time-consuming, even with our use of
coarser screens and greater water volume, with
few fossils recovered relative to the volume of
sediment screened. To continue to screen using
the protocols of previous years would have
required several more field seasons of work,
which was impractical for several reasons.
To begin with, the vertebrate fossils recovered
from the Spoil Pile in 2011 were still in reasonably
good shape, despite having been moved twice
from their original gravesite, and having been
exposed to the harshness of several Indiana
winters as they lay in the Spoil Pile. Nevertheless,
the longer the bones remained on the ground, the
greater the likelihood that their preservation
would be compromised.
Secondly, the logistics of putting together
large-scale field parties, year after year, were
daunting. Coordinating schedules of persons
from the two main institutions involved in the
project (INSM and IPFW), given the other
research commitments of all persons involved,
was difficult. Furthermore, the cost of housing
and feeding participants while on-site was sub-
stantial, a clear fundraising challenge.
A third issue was uncertainty over how long we
would be granted access to the Spoil Pile. We had
outstanding cooperation and assistance for our
work from IMI from 1998 through 2011, and
there was no reason to think that this would end.
At the same time our presence in an active
limestone quarry potentially exposed the compa-
ny to legal problems if one of our party was
injured while on site. Furthermore, government
Figure 1.—Indiana State Museum 71.3.144.3014, a
Borophagus right dentary piece found in Pipe Creek
Sinkhole Spoil Pile material in 2012.
90 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE
regulations of mining safety might at some point
change such that it would no longer be permissible
for us to work at the site.
Therefore, it was concluded that 2014 had t o be
our final field season, and that speed of sediment
processing must be emphasized. Although a
painful decision, it was necessary to risk loss of
additional microvertebrate fossils in order to
process sediment more quickly, by routinely using
coarser screens than in previous years at PCS.
Thus 2014 recovery was essentially a salvage
operation designed to target the recovery of
medium-sized and large vertebrate fossils dis-
persed in the remaining intermixed sediments.
However, if concentrations of bone were encoun-
tered, we would switch to finer-mesh screens. As it
happened, this did not occur.
2014 field operations.—The strategy to en-
hance screening of sediments focused on six
aspects of sediment processing and fossil
recovery: 1) using a Bobcat tractor to scoop
and deliver large volumes of sediment from the
Spoil Pile to each of three screen units; 2) using
perched soaking vats to soften the cohesive
sediments, and afterward to deliver them via a
sluiceway to the screens below; 3) utilizing large
(12.7-mm or 1/2-in mesh) screens; 4) using two
38.1-mm or 1.5-in firehoses with spray nozzles
on each screen unit; 5) staffing four screeners
on each screen to knead sticky clumps of
sediment and recognize bone on the screen; and
6) scheduling a three-week field recovery
operation.
As in the 2011 field work at PCS, the 2014
screening set-up was located in a field well away
from the main Pipe Creek Jr. quarry. A holding
pond (Fig. 2) provided a water source for the
hoses, and a second, smaller holding pond (Fig. 3)
received waste water carrying fine-grained sedi-
ments from the three screening set-ups (Fig. 4).
One of the screening set-ups was documented in
3D using photogrammetry; see Supplemental
Document for schematic diagrams of the set-up
(see footnote 2 on the first page to access
document). A digital model was generated
following the methods described by Falkingham
(2012), but the nature of the photos meant that a
‘clean’ model could not be generated. Instead, the
‘noisy’ model was used as reference to build a set-
up using primitive polygonal shapes in Autodesk
Maya software. The calibrated camera positions
were then used to re-project the texture onto the
new model; the good alignment of the texture on
the new model demonstrated the accuracy of the
digital reconstruction (Supplemental Animation
1 [see footnote 2 on the first page to access
animation]).
To speed the screening process in 2014, instead
of using shovels and buckets, a Bobcat tractor was
used to scoop up large sediment loads and dump
themintoawateringtroughelevatedonasteel
framework (Fig. 5, component 1 and inset
photograph). A rectangular opening was cut into
the side wall of the trough, and closed from the
inside by a wood gate with a metal handle on the
side facing outward (Fig. 5, component 2). A steel
rod passed through this handle, and wedged in
place at each end on the outer wall of the trough.
On the inside of the trough (Fig. 5, inset), at the
two lateral sides of the opening in its base, two
two-by-fours pieces of wood were attached and
caulked against the steel wall of the trough.
Rubber flaps on the two lateral sides of the wood
gate helped seal the gate against the two two-by-
fours when the trough was loaded. After sediment
Figure 2.—The Pipe Creek Sinkhole (PCS) loca-
tion for screening Spoil Pile sediment. A large
holding pond provided water for our hoses. In the
foreground is one of our pumps that supplied water
to the screens.
Figure 3.—Another view of the screening location.
A small holding pond received wastewater and fine
sediment washed from our screens. This same pond
also receives wastewater from the quarry operations
(large pipe in the background). Our screening set-up
is visible to the right of the pond.
FARLOW ET AL.—RAPID SCREEN-WASHING FOR LARGE FOSSILS 91
was dumped into the trough, the trough was filled
with water, to soften the sediment; the weight of
the water helped press the wood gate against the
two two-by-fours at the sides of the trough
opening. Sometimes the trough was filled with
sediment and water as the final task of a day, and
left overnight to soak, but usually soaking was of
much shorter duration.
To begin screening a load of soaked sediment,
the steel rod passing through the handle in the gate
was removed, and the gate was lifted by a jointed
lever system (Fig. 5, component 3). This lever was
made of two two-by-fours joined by a hinge. At
the lower end of one of the two-by-fours was
attached another, perpendicular two-by-four the
two ends of which served as handles for lifting the
lever. The other, upper two-by-four of the jointed
lever passed through a cable loop attached to the
top of the wood gate. A notch (Fig. 5, inset; white
label) was cut into the lower edge of this two-by-
four, allowing it to rest against the back edge of
the trough until the lever was ready to lift, and
ensuring that the lever was positioned for the
easiest lifting of the gate; a second notch (Fig. 5,
inset; black label) positioned the lever in the
correct position on the screen side of the tub. Two
people in coordination would push up on either
end of the transverse, lower cross-piece of the lever
system, allowing sediment and water to spill onto
a sluice (Fig. 5, component 4) leading to a 0.91-m
32.44-m (3-ft 38-ft), 12.7-mm (½-in) mesh
screen (Fig. 5, component 5). After the door was
lifted, it was still necessary for one or two
person(s) to stand in the trough and push—or
wash with ahose—much of the sediment through
the opening onto the sluice.
Two-by-four supports running transversely
beneath the screens provided extra support
from collapse under the weight of sediment and
water. Fire hoses (38.1-mm or 1.5-in diam) with
adjustable spray nozzles were used to wash the
sediment through the screen; because of the
considerable clay content of the sediment (the
bulk of which was unfossiliferous), a great deal
of tearing clay clods apart by hand was done.
Water and fine sediment that passed through
the screen fell onto a tarp (Fig. 4) beneath the
screen which fed waste into the holding pond.
Figure 4.—Side view of the three screening set-ups.
92 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE
After the fine sediment had been washed
through the screen, the concentrate was picked
and any fossils removed.
This mechanized operation potentially subject-
ed bones to damage through rough treatment.
However, worse mechanical damage was likely
inflicted by the two previous relocations of the
Spoil Pile material.
RESULTS OF FIELD WORK
In Spoil Pile material screened in 2014,
intermixed with the Zone C red clay and the
collateral sediment were patches of dark brown
Zone A sediment of the kind that contained
vertebrate fossils during our in situ work in the
sinkhole. Because in 2014 the Zone A sediment
was a modest fraction of the total sediment in the
Spoil Pile, the productivity of bones retained on
our screens was rather low. On average, one or
two bone pieces were recovered in each Bobcat
tractor scoop load, and many loads were devoid
of fossils. However, over the course of three weeks
of screening, several good specimens were ob-
tained, and all the remaining Spoil Pile sediment
was processed.
Many pieces of fossil wood of various sizes
were recovered (asin previous years of work using
different screening protocols), both from in situ
and Spoil Pile sediment. Although abundant,
much of this material has proved difficult to
identify to particular tree species (cf. Swinehart &
Farlow 2020).
The most common bones found in 2014 were
pieces of turtle shell, some of which will likely be
identifiable at least to genus. Turtle limb bone
Figure 5.—Digital image (created by photogrammetric modeling; Supplemental animation 1) of a screening
set-up. Numbers on the image correspond to components of the set-up described in the text. Inset shows
inside of a trough in which sediment was soaked prior to screening; the function of the notches in the
horizontal two-by-four of the jointed lever system (component 3) is described in the text. Note that the
horizontal arm of the joint lever system was longer than it appears in the digital image and animation of the
set-up. (Supplemental animations can be accessed by clicking on the ‘‘Supplemental Materials’’ Link on the
IAS Proceedings page at https://www.indianaacademyofscience.org/publications/proceedings.)
FARLOW ET AL.—RAPID SCREEN-WASHING FOR LARGE FOSSILS 93
fragments were also recovered as well as a cervical
vertebra.
Fragmentary bones of larger animals were also
found. The more interesting specimens include
camelids, peccaries, carnivorans, and deer or
deer-like ungulates. By far the most important
specimen collected during our 2014 field work is a
piece of the left dentary of a large canid,
containing a fourth lower premolar and a first
lower molar (Fig. 6), which was recorded in 3D
using photogrammetry (Supplemental Anima-
tion 2 [see footnote 2 on the first page to access
animation]). This bone is almost certainly from
the same individual as the matching right dentary
fragment that prompted our field work in 2014.
The two jaw portions are about the same size, with
thesamedegreeoftoothwear.Alsorecovered
were two carnivoran canine teeth (Fig. 6), which
plausibly come from the same individual. More
speculatively, it is possible that this dental
material derived from the same individual as an
articulated canid foot collected from in situ
sediments in the sinkhole (Farlow et al. 2010b:
Fig. 26A).
The Spoil Pile is now gone and sampling of the
Pipe Creek Sinkhole fauna is virtually complete,
though descriptive work of the paleobiota is on-
going. It was disappointing that the 2014 field
work did not recover any new cheek teeth of large
mammals other than the borophagine canid.
Interestingly, as in previous years of field work
at PCS, nohorse materialwas discovered. This is a
truly surprising result, given the abundance and
diversity of horses in most late Neogene North
American large-mammal faunas (MacFadden
1998).
Our apparatus and protocol for rapidly-
processing unconsolidated sediments for large
vertebrate fossils worked well. Although not
recommended in situations where time, resources,
and access to the site are unlimited, and the
sediment to be processed is intact and in situ, it
might prove useful in other salvage operations
where constraints like those we faced are encoun-
tered.
ACKNOWLEDGMENTS
Farlow, Johnson, and Falkingham dedicate
this paper to the memory of our colleague, Ron
Richards, who died while the manuscript was
in press. Ron was a valued colleague and a
good friend, who will be missed by all who
knew him.
This research was supported by grants from
the National Geographic Society (#9408-13),
the Indiana Academy of Science (#2014-10),
and the Office of Sponsored Research, Indiana-
Purdue University Fort Wayne. We thank
Figure 6.—Jaw and tooth material of Borophagus recovered during 2014 field work compared with the
specimen found in 2012. Scale bar in centimeters. From left to right: Cast of the 2012 right dentary piece,
viewed from the opposite side from that illustrated in Fig. 1, shown here to facilitate comparison with the left
dentary piece; left lower canine tooth (INSM 71.3.144.3025); right lower canine tooth (INM 71.3.144.3026;
left dentary piece (INSM 71.3.144.3024) containing a 4
th
premolar and a 1
st
molar (rightmost specimen in this
figure) found during screening; see Supplemental Animation 2 for a three-dimensional model of this dentary
fragment. These four pieces are likely from the same individual. (Supplemental animations can be accessed by
clicking on the ‘‘Supplemental Materials’’ Link on the IAS Proceedings page at https://www.
indianaacademyofscience.org/publications/proceedings.)
94 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE
Irving Materials, Inc. for permission to work in
their Pipe Creek Jr. quarry, and for their
constant interest and support throughout the
years of our field work. Responding to
comments from three reviewers greatly im-
proved our paper.
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96 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE
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Article
Full-text available
The 3D digitisation of palaeontological resources is of tremendous use to the field, providing the means to archive, analyse, and visualise specimens that would otherwise be too large to handle, too valuable to destructively sample, or simply in a different geographic location. Digitisation of a specimen to produce a 3D digital model often requires the use of expensive laser scanning equipment or proprietary digital reconstruction software, making the technique inaccessible to many workers. Presented here is a guide for producing high resolution 3D models from photographs, using freely available open-source software. To demonstrate the accuracy and flexibility of the approach, a number of examples are given, including a small trilobite (~0.04 m), a large mounted elephant skeleton (~3 m), and a very large fossil tree root system (~6 m), illustrating that the method is equally applicable to specimens or even outcrops of all sizes. The digital files of the models produced in this paper are included. The results demonstrate that production of digital models from specimens for research or archival purposes is available to anyone, and it is hoped that an increased use of digitisation techniques will facilitate research and encourage collaboration and dissemination of digital data.
Article
Examination of macrofossils from the late Neogene Pipe Creek Sinkhole in Indiana, USA, yielded 15 distinct plant taxa, one fungal taxon, and six invertebrate taxa. The plant assemblage was dominated by terrestrial taxa both in richness and abundance. Of the 12 terrestrial plant taxa, eight were trees or shrubs including two Carya spp., Corylus sp., Fraxinus sp., aff. Pinaceae, Quercus sp., aff. Rosaceae, and an unknown gymnosperm, possibly Ginkgophyta or Cycadophyta. Fossil nuts of a new species, Carya pipecreekensis Swinehart and Farlow sp. nov., are described. Other terrestrial plant macrofossils include a species of Asteraceae, Vitis sp., Xanthium sp., and Poaceae indet. Charcoalified remains of wood, Asteraceae achenes, and Poaceae crowns suggest fires were an important factor in ecosystem structure. Condition of some of the macrofossils suggests high-energy, post-depositional transport. Aquatic species include the plants Chara sp. and two Potamogeton spp. as well as the animals Helisoma sp., Physa sp., Sphaeriidae, and ostracoda. The terrestrial flora suggests a temperate woodland savanna community with a canopy that includes Carya, Fraxinus, Quercus, Corylus, and Pinaceae, a sub-canopy with Vitis, and a ground flora with a species of Asteraceae and abundant Poaceae. The assemblage shares elements and characteristics with the similarly-aged Gray Fossil Site in Tennessee.
Interstratified kaolinite-smectite from a terra rossa in the Pipe Creek Sinkhole, Indiana
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Argast, A. & J.O. Farlow. 2010. Interstratified kaolinite-smectite from a terra rossa in the Pipe Creek Sinkhole, Indiana. Pp. 61-74. In Geology of the Late Neogene Pipe Creek Sinkhole (Grant County, Indiana). (J.O. Farlow, J.C. Steinmetz & D.A. DeChurch, Eds.). Indiana Geological Survey Special Report 69, Bloomington, Indiana. Cifelli, R.L. (Ed.). 1996. Techniques for recovery and preparation of microvertebrate fossils. Oklahoma Geological Survey Special Publication 96-4, Norman, Oklahoma, 36 pp.
Preservation of fossil bone from the Pipe Creek Sinkhole
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Farlow, J.O. & A. Argast. 2006. Preservation of fossil bone from the Pipe Creek Sinkhole. Journal of the Paleontological Society of Korea 22:51-75.
A new late Neogene ground squirrel (Rodentia, Sciuridae) from the Pipe Creek Sinkhole biota
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  • Farlow
Goodwin, H.T. & J.O. Farlow. 2019. A new late Neogene ground squirrel (Rodentia, Sciuridae) from the Pipe Creek Sinkhole biota, Indiana. Proceedings of the Indiana Academy of Science 128:73-86.
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Janis, C.M., G.F. Gunnell & M.D. Uhen (Eds.). 2008. Evolution of Tertiary Mammals of North America, Volume 2: Small Mammals, Xenarthrans, and Marine Mammals. Cambridge University Press, Cambridge, United Kingdom. 795 pp.
Diagenetic history of Pipe Creek Jr. reef
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