Nebraska Invertebrate Fossils

Introduction

As of June 6, 2007, there are 338 images in the database. Select from either fossil list (Fossils arranged by Phylum; or by Fossils Arranged by Phylum, then Stratigraphically). The link will take you to the respective database web page from which you can select specific fossils. The number in parentheses indicates the number of images.

Pictured at right, Nebraskacrinus.

Fossils Arranged alphabetically by Phylum

• Fossilized Algae (5)
• Fossilized Arthropods (10)
• Modern Brachiopods (3)
• Brachiopods from the Winterset Limestone (2)
• Cnidarians Lophophylloid Corals from the Ervine Creek Limestone (1)
• Cnidarians Pseudozaphrentoides verticillatus (Barbour), a horn coral from the Beil Limestone Member, Lecompton Formation, Late Pennsylvanian (Virgilian), Cass County (6)
• Crinoid Fossil from the Beil Limestone Member, Lecompton Formation, Late Pennsylvanian (Virgilian), Cass County (1)
• Cnidarians from the Plattsmouth Limestone Member, Oread Formation, Cass County, Nebraska (1)
• Cnidarians, Dissepimental Rugose Coral from the Winterset Limestone (2)
• Chordata (Link to Fossil Fish from Nebraska)

Fossils Arranged alphabetically by Phylum, then Stratigraphically

• Fossils from the Grant Shale (18)
• Fossils from the Hughes Creek Shale Member, Foraker Formation (84)
• Echinoderms, Deer Creek Limestone (1)
• Fossils from the Stull Shale (56)
• Fossils from the Kiewitz Shale Bed, Stoner Limestone Member, Stanton Formation (Late Pennsylvanian, Missourian), Cass and Sarpy Counties, Nebraska (94)
• Echinoderms, Plattsburg Formation (2)
• Fossils from the Bonner Springs Shale (52)

Additional Information

1. See the explanation of "Lithology (kind of rock) and Morphology (body structure) of Fossils" (see below).
2. Range and Distribution of Nebraska's Invertebrate Fossils (another fossil resource on this web site)
3. For Vertebrate Paleontology information, visit the Discover Your Nebraska County Fossils web site, by Greg Brown, University of Nebraska State Museum.

Links

• Oceans Of Kansas Paleontology - Fossils from the Late Cretaceous Western Interior Sea
• Old As the Hills
• A Guide to the Orders of Trilobites

Lithology (kind of rock) and Morphology (body structure) of Fossils

Geologists who have worked in the late Pennsylvanian and early Permian strata that are exposed throughout the mid-continent have observed that rock sequences are often repetitious. They have attached the name cyclothem to these kinds of deposits. R. C. Moore in Kansas, T. Mylan Stout in Nebraska and Philip Heckel in Iowa have all worked with these rocks. Cyclothems are usually named for the thick, regressive limestone contained within them. The names for these units that Heckel proposed are used below. The limestone beds alternate with shale beds and these are called from bottom to top:

Nearshore shale: These may include continental deposits near the base and marine deposits near the top. This shows an encroaching sea. The invertebrate fossils found in this unit are large and have thick, ornamented shells.

Transgressive limestone: This unit is a thin, dense limestone that was deposited nearer the shore toward its base and farther offshore near its top. The fossils found near the top of the transgressive limestone are usually small and have thin shells, suggesting they lived in deep, cold water. The richest fossil populations are often found at the contact between the transgressive limestone below and the offshore shale above.

Offshore shale: The offshore shale is usually a dark gray near its base and it grades upward into a black, fissile shale. It was deposited in deep, poorly oxygenated water and there was insufficient sunlight to algae to produce carbonates for limestone. The fossils in the dark gray shale are small and have thin, unornamented shells. The black shale usually contains few fossils that mostly of organisms that sunk to the substrate when they died. These fossils include abundant microscopic conodonts and some spectacular fish remains.

Regressive Limestone: The regressive limestone is very similar in lithology and fossil to the transgressive limestone near its base as the water column was still deep and cold as the sea withdrew. The limestone becomes less dense and more coarsely crystalline nearer the top and the fossils are larger, have thicker shells and more ornamentation that suggests they lived in warmer, shallower water.

At right: A typical cyclothem of late Pennsylvanian age: the standing figure in black and the kneeling figure in light blue are atop a near shore shale. At about hip level to the standing figure you will observe the thin, dense transgressive limestone. The offshore shale begins at about waist level and the base of the regressive limestone is is at about head level of the standing figure. The offshore shale of a new cyclothem is above the top of the thick, regressive limestone where the slope changes from nearly vertical to about thirty degrees.

Nebraska Invertebrate Fossils was compiled by

l	Roger K. Pabian Research Geologist, Emeritus 610 Hardin Hall 3310 Holdrege Streets University of Nebraska-Lincoln Lincoln, Nebraska  68583-0996 Phone 402-472-7564 Fax 402-472-2946 rpabian1@unl.edul