Fossils along the Potomac River, Maryland / Virginia. Paleocene Fossil Shark Teeth.








Fossils that can be found along the Paleocene Cliffs of the Potomac River



Printable Identification Fossil Sheets for Vertebrates and Invertebrates of the Paleocene Potomac River



Nearby Shark Tooth Collecting Location:
Calvert Cliffs, MD



Fossil Shark Gallery



Parts of Sharks that Fossilize



Shark Evolution





Fossils Found on the Potomac River in Maryland & Virginia
Fossil Identification for the Aquia Formation - Paleocene

Fossils along the Potomac include:

Shark Teeth, Other Shark Parts, Skates and Rays, Reptiles, Gastropods,



Shark Teeth

Anomotodon novus (Winkler 1874b)
(Extinct Goblin Shark)

These Goblin sharks are a smaller genera than the living goblin sharks, and the goblin shark fossils found at Big Brook.
The teeth rarely exceed 1 inch, and are very slender, and the enamel is smooth. They look like Sand Tiger Teeth (Carcharias sp.).
One way to distinguish them from Sand Tiger teeth is they are very slender and do not have the large cusps that sand tigers do, the laterals instead, have an enamel shoulder, while the anteriors have a very reduced cusp. If the tooth is very worn, it is nearly impossible to distinguish it from a small sand tiger tooth.

For information about Goblin sharks including pictures and vidoes, go to the Goblin Shark Gallery
goblin shark tooth
These are a type of Goblin shark. They are smaller than the extant Goblin shark. They are fairly common along the shores of the Potomac, however, if worn, they are difficult to identify.
Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac river, Charles Co., MD
    Size:
  • Largest one is ~3/4" (19mm)


  • Carcharias hopei (Agassiz, 1843b)
    (Sand tiger shark)

    Sand tiger teeth are very hard to identify, the key to identifying this species from the other sand tigers in the sedements is their smooth enamel. (no striations).
    These teeth are abundant.
    The left most tooth is a profile view. All teeth are anteriors except the rightmost one, which is a lateral. The top tooth is a lingual view, all others are labial views.
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac river, Charles Co., MD
    Size:
  • Largest one is ~1 1/2" (36mm)

  • Cretolamna sp. (appendiculata?)
    (Mackerel-type shark)
    This tooth is very small and a little to worn to make a posative identification, but it probably is a C. appendiculata.
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • ~5/16" (10mm)

  • Otodus obliquus (Agassiz, 1843b)
    (Giant Mackerel-type shark)

    These self evident teeth are the second most sought after teeth in the Aquia formation (the first is the rare Palaeocarcharodon orientalis). O. obliquus teeth can reach slant heights of up to 4", however anything over 2.5" is rare for this location. However, small teeth (~1") are fairly common.
    To some, Otodus is thought to have evolved into the ancestor of Carcharocles spp., including the final species, C. megalodon.
    To Read about Megalodon Evolution, and how Otodus fits into this lineage, click here.
    otodus fossil shark tooth
    The Otodus fossil shark teeth found along the Potomac River are smaller than their Moroccan counterparts. They are usually around an inch in size. Sometimes shark teeth over 2" can be found.
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac river, Charles Co., MD
    Size:
  • Largest one is 1 3/8" (35mm)

  • Paleocarcharodon orientalis (Casier, 1960a)
    (Pygmy White Shark)

    These enigmatic teeth are the most sought after teeth in the Aquia formation, and probably some of the more sought after teeth in general. This is because these sharks only existed for a brief geologic time. They seem to have appeared in the Paleocene, then quickly vanished in the Paleocene. This means they also have a very limited geologic range. In North America they are mainly found in a unit of the Aquia formation. They are also found in parts of Morrocco and Russia.
    These teeth look similar to a great white shark, but probably have nothing to do with them. Paleocarcharodon was probably a dead end lineage. They have irregular coarsly serrated blades, and often have coarsly serrated cusps. The average size of these teeth in the Aquia formation is around an inch (2.54 cm).

    paleocarcharodon fossil shark tooth
    This is a rare tooth, and the only one I have found.
    This specimen has worn serrations, and probably had cusps that are worn off.

    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • 7/8" (22 mm) Date:
  • Sept. 2008 trip

  • Paleohypotodus rutoti (Winkler, 1874b)
    (Sand tiger/Mackerel-type shark)
    These teeth can be identified by their broad crowns, elongated root lobes, and two-three triangular cusplets.
    The first is a posterior, the second is a lateral
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • They can get up to an inch in length, the posterior one is ~ 5/8" (32mm)

  • Striatolamia striata (Winkler, 1874b)
    (Sand tiger Shark)

    The key to identifying Striatolamia sp. from Carcharias hopei is that Striatolamia sp. have striations on their enamel, where Carcharias hopei do not.

    These fossil shark teeth are abundant, especially small ones of less than 1".
    In this image, the box shows what the striations look like. They are tiny grooves that run up the enamel of the teeth. if you run your fingernail over them it feels like grooves in a record (if you know what a record is!). The striations may be worn off on very worn striatolamna teeth.

    The Carcharias teeth found here DO NOT have striations, only Striatolamnia teeth do.
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • Largest one is ~ 1 5/8" (41mm)

  • This is the largest Sand Tiger Shark Tooth I found. It is actually, the largest Striatolamia I have ever seen!
    It was the 1st nice tooth found with the glass-bottom bucket.
    Click here to see a pic of when it was found.
    Formation:
  • Aquia Formation
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Belvedere beach, Potomac River, VA
    Size:
  • ~ 2 1/4" (57mm)
    Date:
  • Fall 2002




  • Other Shark parts


    (Shark Verteberal Centrum)
    Vertebra from sharks
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • Largest one is ~5/8" (16mm)


  • Myliobatiformes order
    (Rays)


    Rays are related to Sharks and Skates, as they are all in the Chondrichthyes Class. Fish in this class have a skeleton made of cartilage instead of true bone. What this means for the fossil collector is bones from these animals seldom fossilize. Occasionally a vertebra may be found, however mostly the hard shark teeth and ray crushing plates are found.


    Myliobatidae family
    (Eagle Rays)


    Myliobatis sp
    Ray crushing plates


    Rays have modified teeth that form flat crushing plates. These crushing plates are adapted for eating mollusks and crustaceans on the sea floor. They suck their prey up like a vacuum and simply crush them between their upper and lower crushing plates.

    The first one is the central part of a ray dental plate, the second is one broken in half.
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • The complete one is ~1 1/4" by 1 1/2" (30x37mm)



  • Reptiles


    Crocodilia order
    (Crocodiles)

    Crocodile bone fragments and teeth are fairly common along the Paleocene Potomac River. However, identifying them to a particular genus is very difficult unless one has skull material. Three common crocodiles in the Aquia formation are the larger Thoracosaurus and Hyposaurus sp., and a smaller Eosuchus sp.


    Crocodile Teeth

    Crocodile teeth come in all shapes and sizes, and are usually black.
    Identification to a particular genus is nearly impossible due to the size and shape variation between individual dentitions.
    Croc teeth are very common along the beach
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • largest one is ~1 5/8" (40mm)

  • Crocodile Skull Fragment
    Eosuchus minor

    This is a fragment from the skull of a smaller crocodile, Eosuchus minor, found along the potomac. A nice geologist and website visitor correctly identified this fossil for me. Thanks!

    Notice the suture lines in the skull fragment.
    crocodile fossil skull fragment of eosuchus minor from the Potomac River, Maryland - Paleocene - Aquia Formation
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • ~ 1.75" (45mm)
    Date:
  • June 2002

  • Crocodile Humerus Fragment
    Probably Thoracosaurus sp. or Hyposaurus sp.

    While bone fragments of crocodiles are often found, identifiable ones are less common. This is the distal end of a right humerus from a rather large crocodile.
    Since it is so large, it may have come from a larger crocodile species, either Thoracosaurus sp., or Hyposaurus sp.
    crocodile humerus fragment of from the Potomac River, Maryland - Paleocene - Aquia Formation
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • ~ 1.75" (45mm)
    Date:
  • June 2002

  • crocodile scute fragment

    Crocodile scutes are a common find in the paleocene deposits along the river.
    Scutes serve as a kind of body armor. They are bone plates just under the skin throughout most of a crocdiles head, neck, back, and upper half of the tail.
    Scutes also serve to warm the crocodiles blood (as crocs are cold blooded animals). Blood collects in the little dimples on the scutes, when the crocodile basks in the sun, the blood in the dimples warm up and circulate through the crocodiles body.

    Crococile scutes can be differentiated from turtle scutes, as the dimples in crocodile scutes are much deeper than in turtle scutes.
    This is a fragment of a larger scute. Notice the large dimple pattern in it.
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • ~ 3.5" (89 mm)
    Location:
  • Sept. 2008 trip


  • Testudine order
    (Turtles)

    Turtle material is common in this formation.


    Turtle plastron fragment
    This is a scute from of the bottom of a turtle shell (the plastron). There are no patterns on the plastron, so it is very difficult to determine what type of turtle this came from.
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • ~5 1/4" (134mm)

  • Trionychidae family
    (Softshell Turtles)

    Trionyx sp.
    Freshwater turtle

    Scutes from the carapace of Trionyx are readily identifiable by their deep intricate patterns (which can be seen in both images). They are different from crocodile scutes in that the dimples in a crocodile scute are much deeper.
    This is a carapace scute from the top of the turtle shell (the carapace). Notice the ligament-like attachment protruding in the side view of the scute.
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • ~2" (50mm)
  • This is another Trionychid scute fragment from the carapace. Notice the self evident pattern, making these scutes easy to identify.
    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • ~2" (50mm)



  • Gastropods

    Turritella sp.
    (Gastropod)
    Internal Molds
    Along some parts of the cliffs, the matrix is harder than the gastropod shells. So the shells erode, and internal molds are left behind. At times, entire cliffsides are composed of these molds


    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • range from ~1"-5" (26-126mm)
  • Here is a matrix chunk with lots of turritella molds in it.

    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • range from ~1"-5" (26-126mm)
  • Along other cliffs of the Potomac, the matrix is softer, so the shells are preserved.

    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • range from ~1"-5" (26-126mm)
  • Here is a matrix chunk with lots of turritellas in it.

    Formation:
  • Aquia Formation, Piscataway Member
    Age:
  • Paleocene, ~56-59 m.y.
    Location:
  • Potomac River, Charles Co., MD
    Size:
  • range from ~1"-5" (26-126mm)