This collection of fossils was collected by Robert Springfield in mines in southern Tennessee and northern Alabama. They contain many fossils from the Carboniferous Period, ranging from 330,000,000 -300,000,000 BCE. The period was defined by the large deposits of coal beds that it left behind. This massive amount of coal was because of the development of bark bearing trees and the fact that a lower sea level during this age left behind large lowland, swampy forests. Plant life during the period was diverse, and although this collection of fossils contains several different genera and species, they all fit into one of three categories: sphenopsids, lycopods and pteridosperms.
Sphenopsids are the ancestor of the modern Equisetum, or horsetails. Like the majority of these fossils, sphenopsids were most common and most diverse during the Carboniferous and declined in population during the Mesozoic and Cenozoic periods. These plants would grow along the waterfront of lakes and rivers, densely packed together with large but shallowly buried roots. They were much larger than modern horsetails and produced secondary xylem, meaning they were woody, unlike Equisetum. They are similar to modern horsetails in that they have hollow stems and segmented trunks. Calamites were the most common genus, and there is an abundance of well-preserved Calamites fossils. Calamites would grow to a height of around 100 ft. Asterophyllites was the organ genera of the leaves of Calamites, growing in a whorled pattern as can be seen on several of the fossils. Sphenopsids used reproductive cones full of spores to reproduce, and was the only plant group of the period to asexually reproduce.
Lycopods were ancestors of club mosses. Unlike modern club mosses, which only grow to about a foot in height, lycopsids reached heights of about 165 ft. high, making them the largest plants of the Carboniferous period. Although they are related to club mosses, they were trees. The growth of lycopsids was much different from that of typical trees, they would grow a vertical leafy trunk without branches until reaching maturity, and would then form a "crown" of branches at the very top of the tree. This crown was solely for the purpose of reproduction, so the tree could disperse its seeds from a tall height. Lepidostrobus was the reproductive cone at the end of the Lepidodendron stem that grew at the crown of the tree. They had a monocarpic reproductive strategy, meaning that once they set their seeds they would die. The fact that they did not have branches for the majority of their lifespan meant that the forests they grew in would be open and full of light. This method of growth and reproduction combined with the fact that lycopsids did not have much wood meant that they had a very short lifespan, they would only live an estimated 10-15 years. Stigmaria, the roots of lycopsids, are the most common fossils. Similar to the roots of sphenopsids, their roots would be very shallow in the ground, which suited the swampy ecosystems they lived in. Stigmaria served as the main anchoring system as well as being the main source of nutrients and water. They would branch dichotomously, meaning one root would branch to two, two would branch to four, four would branch to eight and so on.
Pteridosperms are another common group of plants from the Carboniferous period. Although their leaves resemble modern ferns, they were gymnosperms, meaning they were seed producing plants. They were originally believed to be an ancestor of modern ferns until 1904, when paleobotanists Frank Oliver and Dukinfield Henry Scott discovered that the seeds Lagenostoma and the fronds Lyginopteris had the same glandular hairs, and made the connection that the seeds and leaves came from the same plant. In addition to Lagenostoma, Trigonocarpus and Holcospermum were other common genera of the seeds. The seeds of pteridosperms were fairly large, typically over 100 mm long. The most common pteridosperm fossils are the Neuropteris fronds, and are the only pteridosperm fossils represented in this collection. Neuropteris would have been the leaves of Medullosales, an order of pteridosperms found during the Carboniferous. These plants would have been around 10 m tall and grew near the banks of rivers.
The physical exhibition, consisting of 16 fossils, is on view at the John Crerar Library's First Floor Reading Room for the 2014-2015 academic year. It was curated by Benjamin Rhind, University of Chicago Laboratory Schools high school senior.
The University of Chicago Library is grateful to the Springfield family for their gift of fossil specimens, which brings unique materials to the Library's collections. The Robert Springfield Fossil Collection is on loan from the Library's Special Collections Research Center.
This Web exhibit was produced by Benjamin Rhind with the assistance of Deb Werner. Bradley Busenius provided technical and graphic design support.
Agashe, Shripad N. Paleobotany: Plants of the Past, Their Evolution, Paleoenvironment and Application in Exploration of Fossil Fuels. New Delhi: Oxford & IBH Publishing Co. 1995. Crerar QE905.A350 1995
Andrews, Henry N. Ancient Plants, and the World They Lived In. Ithaca, NY: Comstock Publishing Co. 1947. Crerar QE905.A55
Batten, D.J. and Derek E.G. Briggs, eds. Studies in Palaeobotany and Palynology in Honour of N.F. Hughes. London: The Palaeontological Association. 1986. Crerar QE905.S783 1986
Briggs, Derek E.G. and Peter R. Crowther, eds. Palaeobiology II. Malden, MA: Blackwell Science Ltd. 2001. Crerar QE719.8 .P34 2001
Cleal, Christopher J. and Barry A. Thomas. Plant Fossils of the British Coal Measures. London: The Palaeontological Association. 1994. Crerar QE919.C44 1994
Oleksyshyn, John. Fossil Plants from the Anthracite Coal Fields of Eastern Pennsylvania. Harrisburg, PA: Pennsylvania Geological Survey. 1982
Taylor, Thomas N. and Edith L. Smoot. Paleobotany. Vol. 1, Precambrian through Permian. New York: Van Nostrand Reinhold Company Inc. 1984. Crerar QE911.P340 1984
Taylor, Thomas N. and Edith L. Taylor. The Biology and Evolution of Fossil Plants. Englewood Cliffs, NJ: Prentice Hall. 1993. Crerar QE905.T390 1993
Tidwell, William D. Common Fossil Plants of Western North America. Washington, DC: Smithsonian Institution Press. 1998. Crerar QE935.T5 1998
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|A piece of a stem belonging to Calamites. Calamites were the most common genus of sphenopsids during the carboniferous, leaving many well preserved fossils such as this one. These stems were hollow, meaning that when the stem broke off from the tree they would fill with dirt and sediments, which is why Calamites stem fossils are so common.|
|The outside of a lycopod root of the genus Stigmaria sp. These roots would be very shallow in the ground, but served as the main source of nutrients and anchoring for the tree.|
|This example contains several fossils. The top left corner and bottom right are fossils of Aneimites sp., a pinnule of a pteridosperm. The fossil in the middle is Neuropteris sp., a different pinnule of a pteridosperm. These are two commons genera of Pteridosperms.|
|Another fossil belonging to the genus Neuropteris sp. Although these leaves look just like modern ferns, unlike their modern day equivalent they produced seeds, making them gymnosperms.|
|A very small fossil of the genus Asterophyllites, the organ genera of the leaves of Calamites.|
|Two fossils of pteridosperm foliage. Most likely another example of Neuropteris but the small size of the fossils makes it difficult to determine.|
|A very clear fossil of Lepidostrobus sp., the spore producing cone of a lycopod. This was critical to the lycopods' reproduction. After reaching maturity the lycopods would grow a crown of branches at the top of the tree to be able to release these cones from a higher point.|
|This specimen contains multiple pinnules of Neuropteris sp.|
|A very clear fossil of Asterophyllites sp. clearly displays the whorled branching pattern of the leaves.|
|A cast of a lycopod root. The root was hollow and filled in with sediments, saving the shape of the inside of the root, which is what this fossil shows.|
|Another cast of a lycopod root, Stigmaria sp. The left side of the fossil shows several clear root casts, while the right side of the fossil shows several rootlets.|
|An unidentified fossil although it is most likely another cast of a lycopod root.|
|An extremely clear specimen. It is a branch of Calamites sp. that shows multiple spore producing cones of a sphenopsid. The nodes of the stem are easily seen among the cones, as the cones branch out from the nodes.|
|This specimen contains multiple fossils, mainly several pinnules of Neuropteris sp.|
|The larger specimen has several fossils, stems of a sphenopsid, most likely Archaeocalamites sp. while the bottom left hand corner has a fossil of a spore producing cone of a sphenopsid. The smaller specimen contains the fossil of some foliage of a pteridosperm, most likely Asterophyllites sp.|
|The fossil in the middle is a leaf of a pteridosperm. The bottom of the specimen shows several leaves of lycopods, characterized by being long, narrow and strap-like.|