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Nebraska Invertebrate Fossils - Fossils from the Hughes Creek Member, Foraker Formation

K. C. Heald (1916) applied the name Foraker Formation to rocks that are exposed in the vicinity of Foraker, Osage County, Oklahoma. In its type locality, the Foraker Formation is about 75 feet (23 m) thick but the Foraker is only about 40 feet (12 m) thick in southeastern Nebraska. The Foraker Formation has three members, in ascending order: The Americus Limeston, the Hughes Creek Shale, and the Long Creek Limestone.

M. Z. Kirk (1896) named the Americus Limestone for the village of Americus, Lyon County, Kansas, where it is about 7 feet (2.6 m) thick. In southeastern Nebraska, the Americus Limestone is usually only about 2 feet (0.7 m) thick. It is usually dense, finely crystalline, fossiliferous, and may be the transgressive limestone of a cyclothem. The Americus Limestone may have three to five beds that are separated by thin shale seams in the southeastern Nebraska outcrop area. The Americus Limestone heralds the return in the midcontinent of sedimentation patterns that were more similar to those observed in the older (late Pennsylvanian) Missouri and early Virgil series.

G. E. Condra, 1927, originally applied the name Hughes Creek Shale to up to 50 feet (16 m) of blue, clayes shale, dark shale and thin limestone beds for Hughes Creek, south of Auburn, in Nemaha County, Nebraska. Subsequent workers (Moore and Condra, 1932; Condra, 1935, Moore, 1936, and Burchett) revised the Hughes Creek Shale and beds now called the Oaks Shale, the Houchens Creek Limestone, and Stine Shale were removed from the lower part of the Hughes Creek.

Condra (1927) named the Long Creek Limestone for the beds that immediately overlie the Hughes Creek Shale for cavernous (vuggy?), irregular beds that are exposed on Longs Creek at the foot of the bluff west of the cemetery at Auburn, Nemaha County, Nebraska.

Holterhoff and Pabian (1990), Pabian and Boardman (1995), and Pabian and Diffendal (1989, 1991, in press) recorded several outcrops of the Foraker Formation in Richardson and Pawnee counties.

Pioneer geologists such as F. B. Meek, F. V. Hayden, J. Marcou, and H. B. Geinitz who worked in Nebraska in the 1850's and 1860's first described many of the fossils that are illustrated below.

Many morpholgic terms are used in describing the fossils below. You are referred to any standard text book on invertebrate paleontology to see how these features relate to the body of the living or fossil animal.

Slab of Fossiliferous Limestone

  • Date Entered: 03/01/03
  • Description: This slab of fossiliferous limestone from the upper part of the Hughes Creek Shale Member of the Foraker Formation contains more than 20 different fossil species. Such fossils document the abundance and diversity of life forms in the seas that covered southeastern Nebraska and most of the North American Midcontinent during the Early Permian.
  • Database ID: 19
Slab of Fossiliferous Limestone

Phylum Cnidaria

Phylum Cnidaria (=Phylum Coelenterata) Corals, Jellyfishes, Sea Anemones.

Lophamplexus sp. cf. L. eliasi

  • Date Entered: 03/01/03
  • Description: "?Lophamplexus sp. cf. L. eliasi" Moore and Jeffords. Lophophylloid corals are relatively scarce in the Hughes Creek shale. These specimens are tentatively assigned to Lophamplexus eliasi because of their resemblance to the illustrated type specimens, some of which were collected from the Foraker Formation in Kansas and Oklahoma. The Nebraska examples were collected in Richardson County from the regressive upper part of the Hughes Creek Shale where shallow, warm water environments existed when these sediments were deposited. The polyp (living coral animal) has tentacles equipped with stinging cells that surround a centrally located mouth and it lived in the depression at the top of the conical corallite. The "corallite" or stony skeleton has horizontal dividers called "tabulae" and vertical dividers called "septa" that may converge in the center to form a columella.
  • Database ID: 20
Lophamplexus sp. cf. L. eliasi

Phylum Ectoprocta

Phylum Ectoprocta (=Phylum Bryozoa) Moss Animals. Ectoprocts are also known as bryozoans, but the former name has priority in scientific use since it was the first published. They are commonly called moss animals as the living colony resembles a clump of moss. The stony colony is called zooarium and the individual living chamber in each pore is called a zooecium. The animal that lived inside the zooecium is called a zooid. In the living ectoproct, a ring of tentacles surrounds a centrally located mouth, and the anus is situated outside the ring of tentacles. By retracting a set of muscles, the zooid can move in and out of the zooecium which is covered with a lid-like structure called an operculum. Ectoprocts are all suspension feeders that rely on food particles that are carried by ocean currents or are settling to the substrate from the water column above.

  1. Fenestrate Ectoprocts

    Fenestrate Ectoprocts are ectoprocts whose colonies appear to be like windows in a wall.

    2. Septopora sp. cf. S. conradi

    • Date Entered: 03/01/03
    • Description: "Septopora sp. cf. S. conradi" Condra. Part of frond showing fenestrate or window-like morphology. Note that the large, window-like structures are not the zooecia. The zooecia are tiny pores that cover the solid parts of the zooarium and magnification of about 5 power is needed to observe them clearly. Fenestrate ectoprocts attach to the substrate by a holdfast-like structure.
    • Database ID: 21
    Septopora sp. cf. S. conradi
  2. Branching Ectoprocts

    3. Rhombopora lepidodendroides

    • Date Entered: 03/01/03
    • Description: "Rhombopora lepidodendroides" (Meek). The genus "Rhombopora" derives its name from the rhombus or diamond-shaped zooecia openings. This species "lepidodendroides" derives its’ name from the fact that its zooaria resemble a miniature "Lepidodendron", a fossil-stem genus of a tree-like plant that is related to the modern day lycopod. Branching ectoprocts usually attach to the substrate by a holdfast-like structure. "Rhombopora" superficially is similar to "Thamniscus" but the former branches but slightly and usually only in a single plane.
    • Database ID: 22
    Rhombopora lepidodendroides

    Thamniscus pinnatus

    • Date Entered: 03/01/03
    • Description: "Thamniscus pinnatus" Condra differs from "Rhombopora" and other branching ectoprocts inasmuch as a zooarium will show numerous branches that extend in many directions.
    • Database ID: 23
    Thamniscus pinnatus

    Cyclotrypa barberi

    • Date Entered: 03/01/03
    • Description: "Cyclotrypa barberi." Ulrich is characterized by massive zooaria that are usually elliptical in cross section, and up to 10 to 12 mm in diameter, compared to "Rhombopora" which is round in Cross section and only has diameters of about 2 to 3 mm.
    • Database ID: 24
    Cyclotrypa barberi

Phylum Annelida

High worms

Serpulopsis sp. cf. S. insita

  • Date Entered: 03/03/03
  • Description: "Serpulopsis" sp. cf. "S. insita" (White). "Serpulopsis" is the small, often twisted and tortuous tube of an annelid worm that was not host specific. "Serpulopsis" may be found either free or attached to many different kinds of invertebrates including crinoid stems and plates, brachiopods, mollusks, and to any hard object that may have furnished a firm substrate.
  • Database ID: 79
Serpulopsis sp. cf. S. insita

Phylum Arthropoda

Joint-legged animals. Class Trilobita

Ditomopyge scitula

  • Date Entered: 03/03/03
  • Description: "Ditomopyge scitula" (Meek and Worthen). Images 79 and 80 are Cephalic (head) and tygidial (tail) views. "Ditomopyge scitula" (Meek & Worthen) is a long-ranging trilobite that has been found in almost all of the marine fossil-bearing Pennsylvanian and Permian rocks in Nebraska and the North American Midcontinent. Pabian (1970) Pabian and Fagerstrom (1972) recorded this species from many outcrops in southeastern Nebraska and Pabian, Borovich and Mapes (1993) constructed a growth series for this species that showed morphologic changes in the cephalons and pygidia of this species throughout its development.
  • Database ID: 80
Ditomopyge scitula

Ditomopyge scitula

  • Date Entered: 03/03/03
  • Description: "Ditomopyge scitula" (Meek and Worthen). Images 79 and 80 are Cephalic (head) and tygidial (tail) views. "Ditomopyge scitula" (Meek & Worthen) is a long-ranging trilobite that has been found in almost all of the marine fossil-bearing Pennsylvanian and Permian rocks in Nebraska and the North American Midcontinent. Pabian (1970) Pabian and Fagerstrom (1972) recorded this species from many outcrops in southeastern Nebraska and Pabian, Borovich and Mapes (1993) constructed a growth series for this species that showed morphologic changes in the cephalons and pygidia of this species throughout its development.
  • Database ID: 81
Ditomopyge scitula

Undescribed genus and species

  • Date Entered: 03/03/03
  • Description: Class Trilobita, Trilobites. Undescribed genus and species. Unfortunately, the cephalon or head of this trilobite is damaged in such a way that it is impossible to view any diagnostic features. The small number of segements in the pygidium or tail suggest that it probably belongs to a genus that has not yet been described.
  • Database ID: 82
Undescribed genus and species

Phylum Chordata

The vertebrates

Janassa

  • Date Entered: 03/01/03
  • Description: Shark tooth, "Janassa" sp. Shark teeth have proved to be rare in the Hughes Creek and this single tooth that resembles Malzahn’s (1968) illustrated examples of Janassa is one of but two examples of fish remains that have been found in the Hughes Creek to date.
  • Database ID: 95
Janassa

Symphysial dentition

  • Date Entered: 03/01/03
  • Description: Symphysial dentition form unidentified Permian shark or shark-like fish. Symphysial dentition is made up of the whorl of bilaterally symmetric teeth that are situated on the plane of symmetry of the fish’s mouth. That these teeth have no cutting edge suggests that they may have been from a small shark that fed on plankton.
  • Database ID: 96
Symphysial dentition

Platyxystrodus tooth

  • Date Entered: 01/04/06
  • Description: Pavement tooth or shell crushing tooth from shark- or ray-like fish, "Platyxyxtrodus" sp. collected from near Humboldt, Nebraska. Length about 1 inch (2.5 cm).
  • Database ID: 229
Platyxystrodus tooth

Ichnofossils

Ichnofossils, or trace fossils, are not the remains of the plants or animals themselves but the evidence such as a structure, trail or burrow that was made by a once living organism. Ichnofossils have become a very important area of study and there are now journals that are devoted to this area. Hakes (1976) described many trace fossils from four upper Pennsylvanian units in Kansas, and most of these forms have been found in Nebraska. We do not know what animals made many of these trace fossils. In some modern burrows, for example, one animal may make the burrow and several others may move in and share the shelter.

Arenicolites

  • Date Entered: 03/03/03
  • Description: "Arenicolites" is an ichnogenus that is represented by U-shaped burrows when the fossil is complete. Note the example in the center of the image that has one of the twists for half of the U. These fossils are commonly found only in the offshore, dysaerobic facies of the Hughes Creek.
  • Database ID: 97
Arenicolites

Cruziana d’Orbigny

  • Date Entered: 03/03/03
  • Description: "Cruziana d’Orbigny". These burrows have meniscus structures in them and resemble a form that Hakes (1976) referred to as "Cruziana d’Orbigny". These forms have been found mostly in the offshore, dyaserobic facies of the Hughes Creek.
  • Database ID: 98
Cruziana d’Orbigny

Burrows

  • Date Entered: 03/03/03
  • Description: This example shows a branching burrow and a meandering trail. The slab from which these fossils are illustrated contains numerous traces including Asteriacites above. These traces are from the nearshore, sandy facies of the Hughes Creek.
  • Database ID: 99
Burrows

Trypetesa caveata

  • Date Entered: 03/03/03
  • Description: "Trypetesa caveata" [Tomlinson] (1963). Tomlinson (1963) named this kind of boring "Trypetesa caveata" and attributed it to acrothoracican barnacles and assigned his species to an extant genus, "Trypetesa". These kinds of borings are commonly observed on Myalinid bivalves, as in this specimen, and crinoids. Seilacher (1969) suggested this kind of boring was made by a polydorid worm.
  • Database ID: 100
Trypetesa caveata

Wormtube

  • Date Entered: 03/03/03
  • Description: This meandering trail was collected from the offshore, dyaserobic facies of the Hughes Creek Shale. It is much smaller than the trails from the well-oxygenated, nearshore facies of the Hughes Creek.
  • Database ID: 101
Wormtube

More from the Hughes Creek Member

Invert

Exposure of Americus Limestone and Hughes Creek Shale members of the Foraker Formation exposed in southeastern Richardson County. The lower part of the Hughes Creek Shale exposed here contains fewer fossils than it does in the outcrop area in northwester Richardson County. Here, the lower part of the Hughes Creek appears to have been deposited in deeper, dysaerobic water.

 Invert

Exposure of Americus Limestone, Hughes Creek Shale, and Long Creek Limestone in northwestern Richardson County. The Hughes Creek Shale here is generally more fossiliferous here than it is in the outcrop shown in the previous image. Here the Hughes Creek appears to have been deposited in shallower, more oxygenated water than at the site above.

 Invert

Composite section showing rocks of the Admire and council Grove Groups that are exposed in southeastern Nebraska. Inset shows relative thicknesses of units in the Foraker Formation. Modified after Condra. Click to Enlarge

The fossils shown in this page have been collected over a long span of time by both professional geologists and amateur collectors: Professional geologists include Erwin Hinkley Barbour, C. Bertrand Schultz, T. Mylan Stout, George Evert Condra, Maxim K. Elias, John Boellstorff, Peter F. Holterhoff, and A. Allen Graffham. Amateur collectors include W. D. "Ted" White, Bill Rushlau, Barry Sutton, and Mark Van Heel. This page would have not been possible without their contributions.

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