Monday, July 1, 2013



This is the longest post yet at Land of the Dead but please persevere constant reader.  Many people went through a great deal of time and effort in finding these fossils, even if the discoveries were all accidental.


Holes are odd things.  They aren’t so much something as something not -- a space or hollow in a solid object.  Something was removed or is missing to make the hole.  Going down a rabbit hole, as in Alice in Wonderland, has become a metaphor for exploring a new world or delving into the unknown.  The Acme Hole Company, made famous in the Warner Brothers’ coyote and roadrunner cartoons, manufactures portable holes that can be carried and placed anywhere.  Fall into an astronomical black hole and you’ll eventually be drawn out until you are nothing more than separate subatomic particles.  And, of course, we all know people who are holes of one sort or another. 

In past Land of the Dead posts we’ve looked at mining operations that have accidentally turned up important fossils, treasures that would otherwise have remained forever hidden from scientists. Today we’ll look at another case of vertebrate fossils turning up deep in the crust --- fossils found while drilling boreholes.

In the modern world drilling rigs put deep holes in the earth’s crust in the search for water, petroleum, natural gas, etc. These rigs can drill to tremendous depths, the SG-3 hole of Sakhalin-I Odoptu OP-11 Well in Russia reached a depth of 40,502 ft (12,345 meters)!   The drilling went on for 24 years, halting in 1997. But deep drilling has a surprisingly long history.  Drilling for salt brine in the Zigong region of Sichuan, China has a long history extending back 2,000 years. Using a drill system composed of metal rods, and bamboo piping, and powered by human and animal  means, they reached depths of 2000 feet (600 meters).    

The Sakhalin-I Odoptu OP-11 Well.

Drilling is not done with drill bits like those you use to drill a hole in a piece of wood.  The geologists need to see the kinds of rocks being drilled through to identify the age of the rocks, rock type, and the petroleum producing layers. So the drill bits used are cylindrical and carve long cores of rock and sediment that are brought up the shaft for examination. These cores are not thrown away, but permanently stored in vast “core libraries” and can be studied many years later.  In one example we’ll look at from the Permian of Oman, the fossils were found by someone re-examining cores 20 years after they were collected.

Samples from a core (left) and tens of thousands of feet of cores in a core library (right).

Finding fossil pollen and small invertebrate fossils in cores is not uncommon.  In fact, it is those very fossils that geologists look for in the cores to understand the age of the rocks they are drilling to and determine when the sought after layer has been reached and drilling can be ended.

In contrast to pollen and invertebrates, vertebrate fossils are orders of magnitude rarer. Of all the members of any species of vertebrate that lived, only a miniscule, and sometime not even one, became fossilized.  And of those that became fossils, many were destroyed by later geological activity.  Of those remaining, many were exposed on the surface of the earth many, even hundreds of millions, of years ago and were destroyed by weathering and erosion.  It's only those fossils exposed on the surface over the last few hundreds of years, and exposed in areas where scientists were able to get to, that constitute the great paleontological collections held in our museums and other institutions.  However, there remain untold numbers of vertebrate fossils still buried, below the surface, in the our planet's rocky crust --- sometimes many thousands of feet below the surface. 

As inaccessible as those buried fossils are and as unexpected as it might be, the narrow diameter cores sometimes remarkably, against all odds, contain vertebrate fossils.  These are fossils that would otherwise never have been found.  The cores are not wide, maybe 6 inches on average and vertebrate fossils are often scattered and isolated, so the chance of hitting one, essentially by accident, would seem to be infinitesimally small. But not as small as one might think. So what are some of the discoveries made by this most unusual method?  That’s what we’ll explore here.


A bit of explanation of what is in this compilation seems needed.  The list includes larger fossil vertebrate remains that have been found in cores and have been reported in the scientific literature. Given the extremely scattered nature of this literature, I would not be surprised to find that there are published reports which I have missed. However, I believe I have covered all the major discoveries. For each record I have reproduced an image of the specimen (if single) or a representative fossil if many fossils were present.  For a few records no images were published or available.  I have also included an image of a representative of the group the borehole fossil belongs to, to give an idea of the living organisms. In a few cases the borehole fossil was complete enough that such an ancillary illustration was unnecessary. The scientific name and age of occurrence are as reported in the original paper.  I have not tried to update either, although I have noted subsequent papers on the fossils where I am aware of them.   

I am aware of fossil vertebrate remains found in cores that have not appeared in print and have left them out.  I have not included fossils found while digging wells, such as the type of the sauropod dinosaur Neosaurus missouriensis (Gilmore and Stewart 1945). I have also excluded ichthyoliths, which are isolated small teeth, scales, spines, etc. found in cores of deep sea sediments such as those done across the world’s oceans during the Deep sea Drilling Project. There are many publications on ichthyoliths but including them here would greatly increase the length of this list without adding much significant additional information. I have included one ichthyolith based publication as an example of that type of research.  I have also excluded conodonts, jaw-like microfossils that are sometimes, but not always, considered to be vertebrates.  The literature on conodonts runs to thousands of papers and cannot be accommodated here.

With all that out of the way, let’s proceed.  I have arranged the occurrences by increasing depth of discovery so those of you who are impatient and simply can’t wait, well just jump to the end. But you’ll ruin the suspense.

 Depth of discovery: 13.5 ft (4.1m)

Reindeer footprint (mammal)
Actual fossil reindeer print (right) and interpretive drawing of track (right).
Material: Footprint 
Age: 13,635 yrs old
Catalog number: University of Copenhagen, Geological Museum MGUH 28424
Well:  Core was taken through soft Late Glacial through Holocene lake deposits in Denmark.
Reference: Noe-Nygaard, Milan, Hede, and Holm 2007
Comment: This is the first vertebrate track ever discovered in a soft sediment drill core. 

 Depth of discovery: 94 feet (28.6 m)

Climatiid and ischnacanthid acanthodians (fish)
Acanthodian fossils in core (left) and explanatory drawing (right).

Life restoration of an acanthodian.
Material: Spines, scales, and tooth whorls
Age: Upper Silurian or Lower Devonian
Catalog number: Petrobras (Museu de Paleontologia do Cenpes, Rio de Janeiro, Brazil) Cenpes 002-V
Well: SM-504, Enge-Rio Engenharia e Consultoria S.A., near Cachoeira da Porteira village, Amazon Basin, Brazil
Reference: Janvier and Melo 1988

 Depth of discovery: 133 feet (41 m)

Fish and Mammal Coprolites
Material: Fossilized feces
Age: Eocene
Catalog number: Not reported
Well: the only well of the Messel Lake drilling project, near Darmstadt, Germany
Reference: Richter et al 2005
Comment:  A single core through the fossilized lake sediments at Messel Germany recovered abundant fish and rare mammal coprolites from 4.9 m to 132.3 m.  The fish coprolites contained the remains of aquatic invertebrates such as cladocerans and especially abundant midges.  Data from this work was used to reconstruct food webs in the ancient lake and elucidate the evolution of the lake through time.

Depth of discovery: 492 ft (150 m)

Kentriodontid dolphin (marine mammal)
Incomplete upper arm bone of dolphin.
Material: Part of the humerus and a small rib fragment.
Age: Miocene
Catalog number: Transylvanian Basin Collection, Museum of Paleontology-Stratigraphy of the Babes-Bolyai University in Cluj-Napoca, TBM V411
Well: FH 26
Reference: Codrea and Seretan 2004
Comment: This is the only record of a marine mammal from a borehole.

 Depth of discovery: 705 ft (215 m)

Eagle Rays (fish)
Flat, fossil ray teeth (left), living eagle ray (right)

Material: Tooth plates
Age: Oligocene
Catalog number: not given
Well: Coal exploration borehole Zagorje KZ-3/77, Slovenia
Reference:  Mikuz 2010

 Depth of discovery: 720 feet (219 m)

Prothryptacodon albertensis (arctocyonid mammal)
Prothryptacodon albertensis jaw from core (top) and restoration of an arctocyonid mammal.
Material: Incomplete right mandible with teeth.
Age: Paleocene
Catalog number: University of Alberta 1338
Well: Alberta Oil Well Core Hole 66-1, 6 miles west of Balzac, Alberta
Reference: Fox 1968
Comment:  This is the first known specimen of the species. 


Depth of discovery: 778 ft (237 m)

Latviacanthus ventspilsensis (acanthodian fish)

Latviacanthus in core (left) and drawing of jaws showing teeth (right).

Life restoration of Euthacanthus, a close relative of Latviacanthus.
Material: Part of skull and anterior part of body
Age: Devonian
Catalog number: 25-0535, Lietuvos Geologijos Mokslinio Tyrimo Institutas, Vilnius Latvia
Well: Bohrung Nr. 53, Ventspils, Lettland
Reference: Schultze 1982
Comment: This is the first and only known specimen of this genus and species.

 Depth of discovery: 733 – 1,152 feet  (223 – 351 m)

Aetosauripus sp., Coelurosaurichnus cf ziegelangerensis, Rhynchosauroides cf pisanus, Procolophonius sp., Hamatopus sp. (dinosaur, reptile, and amphibian tracks)
Fossil tracks from boreholes. A. Rhynchosauroides.  B. Hamatopus.  C. Procolophonipus.  D.Aetosauroides.  E. Coelurosaurichnus.

Material: Fossil footprints
Age: Triassic
Catalog numbers: Dept. of Geology, University of Birmingham BU 2004, 2008, 2016, 2022, 2023, 2029
Well:  East Worcestershire Water Works Co., Boreholes 3, 4, and 5, approximately 3 miles east of               Kidderminster
References:  Wills and Sarjeant 1970, Sarjeant 1975
Comment:  These fossil footprints were found at several levels in 3 closely spaced boreholes. For the sake of simplicity I have treated them collectively. The borehole was large, about 18 inches in diameter. There has been some dispute about these tracks; the correct scientific names for them, whether some might have been made by invertebrates, and whether some might not even be biological in origin (King and Benton 1996, Lockley and Meyer 2000, Thulborn 1990, 2006). 

 Depth of discovery: 1280 – 1300 feet (390 – 396 m)

Grangerimus sellardsi (mammal: rodent)
Grangerimus jaw with teeth from core.
Material: Right lower jaw with teeth
Age:  Miocene or Oligocene
Catalog number: University of Texas Bureau of Economic Geology 40061
Well: United Production Company no. 32, George A. Ra Well, Bee County, Texas
Reference:  Hibbard and Wilson 1950
Comment: This is the first known specimen of this species.

 Depth of discovery: 2,184 ft (666 m)

Aetosaurus arcuatus (armored reptile)

Aetosaurus scute (white square) in core with staple for scale.
Restoration of Aetosaurus.

Material:  Single boney scute from along back
Age: Triassic
Catalog number: Not reported
Well:  Payne Well, Virginia
Reference: LeTourneau 2003

  Depth of discovery: 2,320 feet  (707 m)

Colymbus parvus (bird: grebe)
Colymbus parvus lower leg bone from core.
 Material: Incomplete part of lower leg (tibio-tarsus).
Age:  Pleistocene
Catalog number:
Well: Standard Oil Company Well, Title and Trust No. 1, Kern Co.,  CA
Reference: Wetmore 1937
Comment:  At the time of its discovery, this was only the second known specimen of this small grebe.

         Depth of discovery: 2,460 feet (750m)

Anisonchus fortunatus (mammal)
Anisonchus fortunatus upper jaw with teeth from core.
Material: Partial skull.  This is the first specimen discovered of this species. The species epithet     fortunatus is in reference to it being found in a well core.
Age: Paleocene
Catalog number:  United States National Museum 12147
Well: Junior Oil Company, Beard no. 1
Reference: Simpson 1932
Comment: This was the first fossil vertebrate from a borehole to be described in the scientific literature.  As Gilmore (1932:4) wryly wrote at the end of his paper “The discovery of  mammal-bearing Paleocene sediments nearly half a mile below the surface in Louisiana (and far below sea level) is a very extraordinary and interesting fact, but unfortunately it can hardly be said to open up a new field for collecting.
       Even more remarkable is that the fact that this specimen did not come up in a core sample. Deep in the drill hole the drill-stem had separated from the pipe.  Equipment was lowered down into the hole to retrieve the drill stem and that retrieval equipment tore out pieces from the wall of the already existing hole. When the drill stem was pulled up the hole it brought up a piece of shale with concretions up with it. One of the concretions contained the partial skull of Anisonchus fotunatus.

 Depth of discovery: 2,543 feet (775m)

Polysphenodon mulleri (reptile)

Preserved portions of Polysphenodon shown in solid white, with restoration of curved position of skeleton hit by core.
Material: Most of a skull, left arm and hand, left leg and foot, and part of tail.
Age:   Triassic
Catalog number: MB R 1032
Well: Unspecified well, vicinity of Hannover, (Hoffmannsthal near Fallersleben), Saschen State, Germany
Reference: Jaekel 1911, Fraser and Benton 1989.
Comment: This is the only known specimen of this genus and species. The original is now missing, but casts of the original are available for study.

Depth of discovery: 2,614 - 2,624 feet  (797 - 800 m)

Deltasaurus pustulatus (amphibian)
Top of right side of Deltasaurus skull from core, snout towards top, "or" is opening for eye.
Material: Right side of a skull
Age: Triassic
Catalog number: Bureau of Mineral Resources no. F21775
Well: Beagle Ridge Bore (BMR 10) South-West Division, Western Australia
Reference: Cosgriff 1965
Comment: This specimen is the first and only known specimen of this species.

 Depth of discovery: 2910-2933 feet ( 887 - 894  m)

Mormopterus nonghenensis (bat), unidentified verspertilionoid and emballonuroid bats, and unidentified rodent

Mormopterus nonghenens teeth from core.
Material: More than 100 mammal jaws and teeth were recovered from the core.
Age: Miocene
Catalog numbers: Because of the large numbers of specimens many catalog numbers have been   assigned.  Details are given in Legendre et al. 1988). A left upper molar (TF 1878) is the type specimen of the new species of bat, M. nonghenensis.
Well:  Nong Hen-1(A) (NHN-1), Thai Shell Petroleum Company, northern Central Plains of Thailand.
Reference: Legendre et al. 1988
Comment:  The fauna is dominated by bats.  This is explained by the fact that the cores were drilled in karst topography which contains many buried and fossilized  cave systems.

Depth of discovery:  3,074 feet (937 m)

Ichthyoliths (fish)
Various fish teeth from DSDP core.
Material:  Diverse assemblage of fish teeth
Age: Eocene - Oligocene
Catalog number: Large number of specimens from closely spaced samples.
Well:  Deep Sea Drilling Project Site  603, North Atlantic.
Reference:  Hart and Mountain 1987
Comment: Here the abundant but isolated fish teeth were used to constrain the date of an important reflector horizon within sediments on the seafloor.
Depth of discovery: 3,174 feet (967  m)

Mimomys primus (rodent)
Material: Very small lower jaws
Age: late  Pliocene – early Pleistocene
Catalog number: unreported
Well: "Crites” no. 1 well, Buttonwillow Gas Field, Kern County, CA
Reference: Hesse 1934

Depth of discovery: 3907-3964 feet (1191 - 1208 m)

Eorubeta nevadensis (frog)
Eorubeta nevadensis skeleton from core, enhanced by UV light.
Material: Two skeletons
Age: Eocene
Catalog number: American Museum of Natural History 7702 and 7703
Well: Standard Oil Company of California Line Unit no. 1, Egan Range, Nevada
Reference: Hecht 1960
Comment: AMNH 7702 is the type specimen for this genus and species. The bone was very difficult to study. It was photographed under ultraviolet light in order to make the bones much easier to see and interpret.  Frog skeletons as complete as this borehole specimen are very rare in the fossil record. 

 Depth of discovery: 4,265 feet (1300 m)

Tycheroichthys dunveganensis (fish)
Drawing of the spectacularly complete skeleton of Tycheroichthys dunveganensis as found in the core.
Material: Complete skeleton.  This is the only known specimen of this genus and species.  The name means “lucky fish from the Dunvegan Formation”.
Age: Cretaceous
Catalog number: Canadian Museum of Nature 52730
Well: Cequel Energy Inc, west-central Alberta.
Reference: Hay et al. 2007
Comment: This is the only known specimen of this genus and species.  It is the most complete fossil vertebrate ever found in a core.

 Depth of discovery: 4,305 – 4,360 ft (1312 – 1329 m)

Aeduella sp., Paramblypterus sp., Sphaerolepis sp. (fish)

Aeduella sp. in core (left) and explanatory drawing of specimens (right).
Material: Several skeletons of various amounts of completeness
Age: Permian
Catalog numbers: Palaontologischen Institute und Museums der Universitat Zurich A/I 1285,
Well: not known
Reference:  Burgin 1990

 Depth of discovery: 5,217 feet  (1590 m)

Protohippus tehonensis (mammal: horse)
The jaw and teeth of Protohippus tehonensis in side and top view.  The curved margin of the jaw is the edge of the core.
Material: Lower jaw bearing teeth, with unidentified skeletal material beneath it
Age: Late Miocene – Early Pliocene
Catalog number:  California Institute of Technology Vert. Paleo. 1825.
Well: Symons Well no. 1, Hogan Petroleum Co., 11 miles southeast of Bakersfield, CA
Reference:  Stock 1935

Depth of discovery: 6145 – 6204 feet (1873 - 1891 m)

Unidentified aistopod and lepospondyl amphibians, Wurdigneria sp. (shark), Triodus sp. (shark), Lissodus sp. (shark), Gnathorhiza sp. (lungfish), unidentified paleoniscoid and acanthodian scales (fish)

Life restoration of a snake-like aistopod amphibian (left) and acanthodian (right).
Material: Fish are known from isolated teeth, scales, and occasional skull bones.  Amphibians are known from isolated vertebrae and teeth.
Age: Permian
Catalog number: Not reported
Well: WAFRA-6, Al Wusta region of Oman
Reference:  Schultze et al. 2008
Comment: This is the most diverse borehole vertebrate fauna reported to date in the scientific literature, containing numerous groups of fish as well as amphibians. The publication by Schultze is a brief preliminary one page report. 

  Depth of discovery: 6,358 – 6,566 feet (1938 – 2001 m)

Unidentified argentinoid and osmeroid fish
Fish-In-A-Fish.  Osmerid fish skeleton from core with smaller argentinoid fish (indicated by arrow) in stomach region.
Material: Multiple fish skeletons from two wells.  One contains a small fish skeleton inside its stomach region.
Age: Paleocene
Catalog number: Geological Museum, Copenhagen  MGUH VP 2927, 3024 and other specimens with no reported numbers.
Wells: Well 25/4-1 (Heimdal field area) and 25/10-2 (Balder field area), Norwegian North Sea
References:  Bonde 1982, 1987
Comment: This is the only vertebrate fossil from a borehole that has preserved stomach contents.

Depth of discovery: 6663 feet (2031m) 
Boney Fish 
The skeleton of Neolycoptera gracilis, skull at the right end.
Material: Multiple fish skeletons from closely spaced wells.  
Age: Upper Jurassic and Upper Cretaceous
Catalog number: Museo de La Plata,  MLP 40-XI-7-1 to 4 (L. patagonicus), MLP 39-6-30-10 to 12 (Bunoderma baini), MLP 39-6-10 1 and 2 (Neolycoptera gracilis).
Wells: Unreported wells, Plaza Huincul, Argentina
References:  Dolgopol 1939, 1940a, b; Arriata and Cione 1996, Cione and Pereira 1990 
Comment:  The fossils occurred at several levels (Neolycoptera gracilis from 6663 ft, Leptolepis patagonicus 24477-3281 feet, and depth unreported for Bunoderma baini).  I have grouped them together here for convenience.

  Depth of discovery: 8,579 feet  (2615 m)

Plateosaurus sp. (dinosaur)
Human finger points at cross section of Plateosaurus finger bone in core.

Material: Finger bone
Age: Triassic
Catalog number: Paleontological Museum Oslo 207.207
Well: Snorre Field Well 34/4-9s, Norwegian North Sea oil Field
Reference: Hurum et al. 2006
Comment: This is the first dinosaur fossil from Norway.  It was found in a drill core from an offshore drilling platform in the North Sea.

Depth of discovery: 9,210 feet  (2807 m)

Unidentified marine turtle (reptile)

Material:  Part of the shell
Catalog number: unreported
Age: Cretaceous.
Well: Amerada Petroleum Corporation exploratory well approximately 12 miles northwest of Okeechobee
Reference: Olsen 1965
Comment: This is the oldest fossil vertebrate known in the state of Florida. It is on permanent exhibit at the Florida Museum of Natural History.

 Depth of discovery: 10,836 – 10,844 feet (3303 - 3305 m)

Cleithrolepis granulata (fish)
The scaly body of Cleithrolepis granulata as exposed in the core.
Material: Several specimens, mostly of complete fish. 
Age: Triassic
Catalog number: Type specimen is Arabian Gulf Oil Co. (AGC 1424). in Benghazi, Libya. Other specimens deposited in British Museum (Natural History)
Well: Well L4-51, Central Cyrenaica, central Libya
Reference: Gardiner 1988
Comment: These are the first and only known specimens of this species of fish.


Depth of discovery: 12,560 feet  (3828 m)

Qataraspis deprofundis (fish)
The anteroventral plate of Qataraspis (right) and its position (red) in a restored relative, Coccosteus.
Material: Bone of shoulder girdle
Age: Devonian
Catalog number: British Museum of Natural History, Paleontology 41933-4
Well: 4 ½” diameter core, Iraq Petroleum Company bore DK 68, Qatar Arabia, Persian Gulf
Reference: White 1969
Comment: This is the deepest known occurrence of a fossil vertebrate. This specimen is the only one known for this genus and species. The species epithet deprofundis is Latin for “out of the depths.”  How apt!

 Frozen/Fossilized (But Still Living) 50,000,000 Year Old Reptile Flesh, Arctic Circle

In 1961 a group of prospectors, searching for copper, were drilling “somewhere in the forbidding Arctic tundra of Lapland”. The core sample brought up (from an unspecified depth) a chunk of leathery skin and bloody flesh.  There were bones in the flesh, which the crew chief identified as fossilized. The material was ultimately sent to the Copenhagen Aquarium, as was a larger piece of tail found soon after. Ultimately the flesh reanimated and grew into the gigantic and fearsome Reptilicus, a dragon-like cross between a “Diplodocus and an amphibious form”.  Reptilicus decimated much of Copenhagen and the Danish countryside before being destroyed. Well, only sort of destroyed.

I am an unabashed fan of B-grade 1950 - early 1960’s, sci fi movies but Reptilicus is truly among the worse examples of that genre. Reptilicus is a poorly controlled and ridiculous marionette, with acid spit that is rendered in the cheapest and least believable way possible.  I saw this movie when I was about 10 years old and I distinctly remember leaving the theater with the feeling that I had been ripped off by this awful piece of inexcusable dreck. It is a truly infamous piece of sci fi film making and I encourage you to try to track down a copy sometime.  You will never forget it --- try as you might.

Oh, and yes, Reptilicus is the ONLY film monster ever to be discovered in a borehole core.


My deep thanks to Hans-Peter Schultze, Carl Mehling, Adrianna Lopez-Arbarello, Paul Lambers, Emma Rainforth, Anne Warren, Andrea Tintori, Mike Bell, Gilles Cuny, Mikko K. Haaramo, Alberto Luis Cione, Alan Heward, John Hunter, Richard C. Hulbert Jr., Tommy Tyrberg,  George Engelmann, Peter LeTourneau, and other colleagues who over the years have exchanged info about borehole paleontology on the VertPaleo and Dinosaur Mailing List discussion lists and exchanged pdfs or hard copies of publications.


Arratia, G. and Cione, A.L. 1996. The fish fossil record of southern South America. Münchener

Geowissenschaft Abhanlungen 30A: 9-72 

Bellows, A. The Deepest Hole. The Damn Interesting Website, article number 193, 20 June 2006

Bonde, N. 1982. Teleostei (bony fish) from the Paleocene of the Norwegian north-sea drillings, Norsk Geologisk Tidsskrift 62 (1): 59-65

Bonde, N. 1987. Moler --- its origin and its fossils, especially fishes. Skamol. Skarrehage molervaerk a/s: 54 pages

Bürgin, T. 1990. Palaeonisciden (Osteichthyes: Actinopterygii) aus dem Unteren Rotliegenden (Autunien) der Nordschweiz. Eclogae geologicae Helvetiae  83: 813-827 

Cione, A.L. and Pereira, S.M. 1990. Los peces del Jurásico posterior a los movimientos intermálmicos y del Cretácico inferior de Argentina. In Volkheimer, W. (ed.) Bioestratigrafía de los sistemas regionales del Jurásico y Cretácico de América del Sur, Editorial Inca, 2: 385-402, Mendoza 

Cosgriff, J.W.  1965.  A new genus of Temnospondyli from the Triassic of Western Australia.  Journal of the Royal Society of Western Australia 48 (Pt. 3): 65-90 

Dolgopol de Sáez, M. 1949. Noticias sobre peces fósiles argentinos. Revista del Museo de La Plata, Paleontología 14(96): 443-461.

Fox, R. C. (1968). A new Paleocene mammal (Condylarthra: Arctocyonidae) from a well in Alberta, Canada. Journal of Mammalogy 49: 661-664

Fraser, N.C.  and Benton, M.J.  1989. The Triassic reptiles Brachyrhinodon and Polysphenodon and the relationships of the sphenodontids. Zoological Journal of the Linnean Society 96:413-445.

Gardiner, B. 1988. A new Cleithrolepis from the Triassic of Central Cyrenaica, northeast Libya. in El-Arnauti A. (ed) Subsurface  Palynostratigraphy of northeast Libya: 259-265 

Hart, M.B., and Mountain, G.S. 1987. Ichthyolith evidence ofr the age of the reflector Au, Deep Sea Drilling Project Site 603. Deep Sea Drilling Project , Volume XCIII: 739-750.

Hay, M.J., Cumbaa, S.L., Murray, A.M. and Plint, A.G. 2007. A new paraclupeid fish (Clupeomorpha, Ellimmichthyiformes) from a muddy marine pro-delta environment: middle Cenomanian Dunvegan Formation, Alberta, Canada. Canadian Journal of Earth Sciences 44:775-790

Hecht, M.K. 1960. A new frog from an Eocene oil-well core in Nevada.  American Museum Novitates  no. 2006” 14 pages. (available on-line at

Hesse, C.J. 1934. Another record of the fossil vole Mimomys primus (Wilson) from California. Journal of Mammology 15(3): 246

Hibbard, C.W. and Wilson, J.A. 1950. A new rodent from subsurface stratum in Bee County, Texas.  Journal of Paleontology 24(5): 621-623

Hulburt, R.C. (ed.) 2001. The Fossil Vertebrates of Florida. University Press, Florida: 2350 pp.

Hurum, J.H., Bergan, M., Müller, R., Nystuen, J.P. and Klein, N. 2006. A Late Triassic dinosaur bone, offshore Norway. Norwegian Journal of Geology 86: 117-123.

Jaekel, O.  1911  Die Wierbeltiere.  Eine Übersicht über diefossilen und lebenden Formen.Borntraeger , Berlin, 252p

Janvier, P. and Melo 1988. Acanthodian fish remains from the Upper Silurian or Lower Devonian of the Amazon Basin, Brazil.  Palaeontology 31(3): 771-777 

King, M.J. and Benton, M.J. 1996. Dinosaurs in the Early and Mid Triassic? – The footprint evidence from Britain.  Palaeogeography, Palaeoclimatology, Palaeoecology 122: 213-225.

Legendre, S., Rich, T. H. V., Rich, P. V., Knox, G. J., Punyaprasiddhi, P., Trümpy, D. M.,  Wahlert, J. and Napawongse Newman, P. 1988. Miocene fossil vertebrates from the Nong Hen-I(a) exploration well of Thai Shell Exploration and Production Company Limited,  Phitsanulok Basin, Thailand. Journal of Vertebrate Paleontology 8(3): 278-289 

LeTourneau, P.M. 2003.  Tectonic and climatic controls on the stratigraphic architecture of the Late Triassic Taylorsville basin, Virginia and Maryland, USA, in  LeTourneau, P.M. and Olsen, P.E. [eds.] The Great Rift Valleys of Pangea in North America, Volume 2: Sedimentology, Stratigraphy, and Paleontology, Columbia University Press, New York. p. 12-58 

Lockley, M. and Meyer, C. 2000.  Dinosaur Tracks and Other Fossil Footprints of Europe.  Columbia University Press, N.Y.: 323 pp 

Mikuz, V. 2010. Eagle rays (Myliobatidae) from Zagorje Tertiary Basin, Slovenia.  Folia Biologica et Geologica 51(1): 35-44

Noe-Nygaard, N., Milan, J., Hede, M.U., and Holm, J. 2007. A reindeer track from a drill core, and lake basin development of the Late Glacial Lille Slotseng kettle-hole basin, South-East Denmark. Bulletin of the Geological Society of Denmark 55: 85-95

Olsen, S.J. 1965. Vertebrate Fossil Localities in Florida.  Florida Geological Survey no. 12

Richter, G. and Wedmann, S. 2005. Ecology of the Eocene Lake Messel revealed by analysis of small fish coprolites and sediments from a drilling core. Palaeogeography, Palaeoclimatology, and Palaeoecology 223: 147-161 

Sarjeant, W.A.S. 1975. Fossil tracks and impressions of vertebrates. in: Frey, R.W. (ed.) The Study of Trace Fossils. Springer Verlag: 283-324 

Sarjeant, W.A.S. 1996. A reappraisal of some supposed dinosaur footprints from the Triassic of the English Midlands.  Mercian Geologist 14: 22-30

Schultze, H-P., Zidek, J. 1982. Ein primitiver Acanthodier (Pisces) aus dem Unterdevon Lettlands. Palaont. Z. 56:1/2. Pp. 95-105

Simpson, G.G. 1932 a new Paleocene mammal from a deep well in Louisiana." Proceedings of the United States National Museum 82 (no.2943, art. 2): 1-4

Stock, C.  1935. Deep-well record of fossil mammal remains in California. Bulletin of the American Association of Petroleum Geologists, Geological Notes 19(7):1064-1068

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Thulborn, R.A. 2006. On the tracks of the earliest dinosaurs: implications for the hypothesis of dinosaurian monophyly.  Alcheringa 30: 273-311

Wetmore, A. 1937. A record of the fossil grebe, Colymbus parvus, from the Pliocene of California, with remarks on other American fossils of this family. Proceedings of the California Academy of Sciences, series 4, 23(13):195-201

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Wills, L.J. and Sarjeant, W.A.S. 1970. Fossil vertebrate and invertebrate tracks from boreholes through the Bunter series (Triassic) of Worcestershire.  Mercian Geologist  3: 399-414.

In order of appearance

Sakhalin-I: Bellows 2006
Reindeer track: Noe-Nygaard, Hede, and  Holm, J. 2007
Acanthodian remains from Brasil: Janvier and Melo 1988
Acanthodian restoration: Creative Commons  license.
Eagle ray teeth (fossil): Mikuz 2010
Prothryptacdon: Fox 1968
Latviacanthus: Schultze and Zidek 1982
Footprints from Waterworks bores:  Wills and Sarjeant 1970
Grangerimus: Hibbard and Wilson 1950
Aetosaurus scute:  LeTourneau 2003.
Colymbus parvus: Wetmore 1937 
Polysphenodon: Fraser and Benton 1989
Deltasaurus: Cosgriff 1965
Mormopterus: Legendre et al. 1988
Ichthyoliths: Hart and Mountain 1987
Eorubeta: Hecht 1960
Tycheroichthys: Hay et al. 2007
Aeduella: Burgin 1990
 Protohippus:  Stock 1935 
Omerid with stomach contents:  Bonde 1987
Neolycoptera gracilis Dolgopol 1939
Cleithrolepis: Gardiner 1988
Qataraspis: White 1969
Reptilicus and drilling crew: