So far, no vertebrate fossils have been described from outcropping sediments and rocks of the Paleocene Epoch, 57.8 to 66.4 million years B.P., that outcrop within northwestern Louisiana. These strata consist of riverine and deltaic deposits which contain a few thin beds of nearshore marine sediments. Although the marine beds undoubtedly contain shark teeth, fish otoliths, fish teeth, and other vertebrate fossils, none have been formally recorded and described.
The only Paleocene vertebrate fossil described from Louisiana was found under rather extraordinary and unintentional circumstances. This fossil, a portion of a small skull, came from a core accidentally taken at a depth of about 2,460 feet below the surface from an oil well in Caddo Parish. It was recovered during "fishing" operations to recover a parted section of drill-stem in the Junior Oil Company, Beard No. 1 in Sec. 9, T.18N., R.16W. While fishing for the drill-stem pipe, an overshot-fishing-tool was forced and rotated into the side of the hole. When it penetrated the side of the drill hole, the overshot-fishing-tool accidentally cored the sediments forming it walls (Simpson 1932).
When the overshot-fishing-tool was recovered from drill hole, it contained a core of shale with concretions. Among the concretions, Mr. W. C. Spooner found one with a partial skull of a small mammal. He carefully packed and mailed it with a detailed description of the location and circumstances of its recovery to Dr. W. C. Mendenhall for examination. Thus, this unique fossil find came to light because of the foresight and efforts of Mr. Spooner (Simpson 1932).
The fossil itself consists of the partial skull of was then a new species of the subfamily of Anisonchinae. This fossil, named Anisonchus fortunatus, consists of the anterior (back) part of the skull with the left canine and four other teeth. Other fossils of this genus are known only from outcrops of lower and middle Paleocene sedimentary rocks within Mexico and Montana (Simpson 1932).
Concerning this unique fossil find, Simpson (1932, p. 4) states:
"The discovery of mammal-bearing Paleocene sediments nearly half a mile below the surface in Louisiana (and far below sea level) is a very extraordinary and interesting fact, but unfortunately it can hardly be said to open up a new field for collecting."However, Paleocene riverine and deltaic sediments outcrop over a significant part of northwestern Louisiana (Spearing 1995, p. 176). Possibly, outcrops of these strata will yield more fossils of this other Paleocene vertebrates to a persistent and lucky fossil collector.
Simpson, G. G., 1932, A new Paleocene mammal from a deep well in Louisiana. proceedings of the United States National Museum, vol. 82, art. 2, pp. 1-4.
Spearing, Darwin, 1995, Roadside Geology of Louisiana. Mountain Press Publishing Company, Missoula, Montana.
Copyright © 1996-2002 Paul V. Heinrich All rights reserved.