Within Louisiana, strata dating from between 23.7 to 36.6 million years B.P., the Oligocene Epoch, consist of the Catahoula Formation and the underlying Vicksburg Group. At this time, the only known vertebrate fossils from the Catahoula Formation are a couple of bird tracks. Berry (1916) and Chawner (1936) document the presence of abundant leaf fossils within the Catahoula Formation. The presence of sharks teeth and fish otoliths within the discontinuous marine beds have been noted within the Vicksburg Group.
The Catahoula Formation consists of gray to white sandstone, loose quartz sands, tuffaceous sandstones, and brown sandy clay. Locally, these strata contain petrified wood, including the State Fossil, petrified palm wood, and thin beds of volcanic ash. Rivers and streams deposited the Catahoula formation on extensive coastal plains that bordered the Oligocene Gulf of Mexico (Matson 1916, Snead and McCulloh 1984).
The only vertebrate fossils reported from the Catahoula Formation are a couple of bird tracks found on a single slab. These fossils were found near Bentley, Grant Parish, Louisiana by Mr. B. N. Eubanks of Dry Prong, Louisiana. Apparently, these fossils came from the Catahoula Formation (Wetmore 1956).
Both tracks consist of casts composed of either very fine grained sandstone or siltstone. They are casts of strong and robust feet with rather small claws and indication of small webs. Both track casts show three well-defined, relatively short front (anterior) toes and a faint indentation suggestive of the hind toe. They are 97 by 79 millimeter and 86 by 71 millimeter in size. The robust form, spread of the toes, and the small webs indicate that they were made by a condor-like bird, possibly some type of vulture (Wetmore 1956).
The Vicksburg Group consists of deltaic deposits containing discontinuous beds of marine strata that underlies the Catahoula Formation. The deltaic deposits consist of brown to gray lignitic clays with interbedded lignite and micaceous sands. Locally, nearshore marine sediments consisting of discontinuous beds and layers of calcareous shale and bluish fossiliferous clay occur within these deltaic deposits. The marine sediments contain shark teeth and fish otoliths in addition to abundant invertebrate fossils. Currently, information concerning these vertebrate fossils are lacking (Chawner 1936, Snead and McCulloh 1984)
Berry, E. W., 1916, Flora of the Catahoula Formation. U.S. Geological Survey Professional Paper 98, pp. 227-251.
Chawner, W. D., 1936, The Geology of Catahoula and Concordia Parishes. Louisiana Geological Survey Geological Bulletin no. 9, 232 pp.
Matson, G. C., 1916, The Catahoula Sandstone. U.S. Geological Survey Professional Paper 98, pp. 209-226.
Snead, J. I., and McCulloh, R. P., 1984, Geologic Map of Louisiana, scale 1:500,000, Louisiana Geological Survey, (P.O. Box G, Louisiana State University) Baton Rouge, Louisiana (70893).
Wetmore, Alexander, 1956, Footprint of a bird from the Miocene of Louisiana. Condor. vol. 58, no. 5, p. 389-390.
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