Fossil Friday
Geology Staff collected gravel samples in Warren County with the University of Mississippi geology doctoral student Maxwell Pizarro. Max’s primary focus of study is on igneous rocks.
Mississippi is a coastal plain state and all of our geology at the surface is sedimentary in origin. Therefore igneous rocks only occur at the surface here in sedimentary environments, such as a constituent of our gravel deposits.
Only two geological deposits contain igneous gravel rocks. One is the modern Mississippi River alluvium that underlies the Yazoo Basin in the Mississippi Delta region. The other is in the gravels of the ancestral Mississippi River Pre-loess Terrace Deposits which lie perched high above the delta along its eastern valley wall, beneath the thick loess deposits in the Loess Bluff Region.
Max worked with us earlier this week (over his spring break) in sampling our diverse collection of volcanic rocks from the Pleistocene gravels of the Pre-loess Terrace Deposits in western Mississippi. These rocks included extrusive rocks called rhyolite, trachyte, and volcanic tuff.
This week he also went to the field with our geologists to study and sample outcrops of the Pre-loess Terrace gravels in Warren County. His study for this project will be to help describe and source these volcanic rocks to their bedrock origins, some of which are over a billion years in age.
This valuable information will help our scientists mapping the geology of the area understand the dynamics of the evolution of Mississippi River in the lower valley over the course of its glacial history during the Pleistocene.
While conducting field studies for geologic mapping, our MDEQ, survey geologists often find evidence that we are not the first people to visit these, often remote, outcrops. Pictured below is a prehistoric Native American artifact, a crude biface (approximately 18cm in length) that was observed while studying a geologic outcrop in Yazoo County, Mississippi. It exhibits heavy use-wear from preferential battering along one edge. This artifact was fashioned from silicified fossil palm (Palmoxylon), from the Early Oligocene, Forest Hill Formation. Fossil Palm was prized by the early Native American inhabitants for it unique texture and beauty.
30 Million year old fossil pollen and spores samples were taken recently from a lignite bed at this outcrop for palynology study and paleoenvironmental reconstruction of these ancient deposits. This same geologic layer also bears large-diameter root bulbs of these fossil palm stumps, and the artifact was presumably a product of reduction of these silicified stumps for lithic material procurement, representing the evidence of an ancient mining practice. Stone tool artifacts made from fossil palm are well-documented from nearby prehistoric sites along the Yazoo River and likely originated from this and other nearby outposts.
A poster on this paleobotanical research on the plant fossils we collected from the Forest Hill Formation was given recently at both the Botanical Society of America and last month at the Mississippi Academy of Sciences on the details of our findings. This work was authored by a collaboration between Delta State University, the Smithsonian Institution, and MDEQ, geologists with the State Geological Survey.
A detailed geologic map, including the aspects of the paleontology and geoarcheology of the area is due to be published by our office this July through a cooperative mapping grant with the United States Geological Survey’s StateMap program.
What was it like millions of years ago? We can study the fossil bones, teeth, and shells of long extinct animals, but how do scientists know what rest of the details to make a picture of what the world they once lived in, so long ago, looked like? Our researchers at MDEQ’s Office of Geology frame that picture with the multifaceted research involved in what they do in geologic mapping projects. Geology not only provides information about our natural resources and provides the foundation for the environment that currently inhabits it, studying it also is our window into the environments of the deep past. This week MDEQ’s Surface Geology mapping staff field checked outcrops of the Forest Hill Formation for newly-drafted geologic maps soon to be published on Cox Ferry area of Yazoo County, Mississippi. The Forest Hill Formation consists of alternating sands and clays from formed in a coastal delta some 30 Million Years Ago. It us sandwiched between the deep marine clays of the Yazoo Formation below and the shallow tropical Vicksburg Limestone above. Further to the south (down-dip), these same are buried deeply by younger geologic formations, There, these sands act as an important fresh groundwater aquifer for the citizens of state and these outcrops we are mapping serve as the aquifer recharge areas for this essential natural groundwater resource. Along the bedding planes, photographed at one of these ancient outcrops off of Cox Ferry Road, a hash of lignitized fossil plant remains was studied this week by our field staff. We know from previous studies that fossil palm (Palmoxylon) dominates the silicified wood found here that once made up the forests along the riparian environments bordering the ancient river delta, but our research team has been learning much more. Office of Geology staff has been collaborating with paleobotanists and palynologists from Delta State University and The Smithsonian Institute to study and photograph the wealth of exquisitely-preserved fossil pollen spores to gain a more complete picture of the plant diversity and the paleoenvironment of the Forest Hill Formation.
If you look very carefully along the nature trail behind the Mississippi Museum of Natural Science, as you descend in elevation from the bluff to the Pearl River swamp, you will begin to notice that there are sea shells everywhere. These are not modern shells brought in with the gravel for the trail but fossils eroding from the bluff. They are from an ancient sea bed from a time long ago called the Eocene Epoch, almost 40 million years ago. The reason this bed of sea shells (called the Moody Branch Formation) are pushed up and exposed there has to do with a much more ancient story, from a much more ancient time. Buried much deeper beneath the Museum is the apex of a large volcanic structure, dating to the days of the dinosaurs during in the Cretaceous period, some 75 million years ago. This was once part of a string of volcanic islands (much like the Hawaiian islands today) that stretched from Jackson, through the Mississippi Delta, and into Arkansas. Please do not collect the shells, because this scientifically important outcrop is part of a Mississippi State Park. Just know their story, appreciate the local geologic history, and please share it with others.
This week, MDEQ Office of Geology research staff conducted a brief field study with museum’s Paleontology program’s George Phillips, Dr. Ezat Heydari faculty of the Earth Sciences program at Jackson State University, and were accompanied by high school student intern Nolan Wells who was job-shadowing with us this week. Featured photo of the week are a collection of perfectly preserved fossil mollusk shells of two specimens of Turritella alveata (Conrad in Wailes, 1854), Lapparia dumosa exiqua Palmer, 1937, and Carycorbula densata (Conrad in Wailes, 1854).
Mississippi has been well recognized by scientists throughout the world and by our own residents as having a wealth of geological resources, especially when it comes to our fossils. Fossils can tell us a great deal about the age and past environment of rock units in Mississippi, so much in fact, they are essential to interpreting our state’s geology.
While fossils from ancient marine environments are often the subject of detailed studies in Mississippi, those from terrestrial environments are just as equally plentiful but still poorly documented and understood. Marine fossils are dominated by the remains invertebrate a vertebrate animals while terrestrial environments chiefly consist of remains of fossil plants.
MDEQ’s Office of Geology’s ongoing collaboration with paleobotanists at Delta State University, University of Southern Mississippi, University of South Alabama, and The Smithsonian Institution are starting to open up a world of new knowledge of our past terrestrial environments with detailed studies of fossil plant sites in Mississippi. These studies have traditionally focused on fossil pollen and leaf fossil studies, but fossil wood in particular have received less research attention.
Fossil wood can be found throughout the state from the Paleozoic times (before the days of the dinosaurs) to the Pleistocene (the last Ice Age). Though much of it may look similar, it isn’t remotely the same stuff. Each formation it occurs in represents a different time period with a different ecology and different species of fossil plants, including trees. The study on fossil wood is very difficult and it is only done by a handful of very specialized scientists. Because of the wealth of fossil wood in Mississippi, we are beginning to reach out and work more with these specialists to open up a world of understanding to what the trees and forest were like throughout geologic time in Mississippi.
The photo features features an exquisitely preserved piece of silicified wood collected on a canoe trip from the Wolf River in Harrison County by Rep. Manly Barton, Mississippi House of Representatives District 109. It is likely derived from the Pliocene age outcrops of the Graham Ferry Formation which outcrop along the stream. This fossil wood is from a tree that grew in an ancient river delta, some 5 million years ago. The forests in this environment existed just before the onset of the Ice Ages of the Pleistocene.
The preservation of this fossil wood specimen is so detailed it is termed “permineralization”, a scientific term meaning that individual structures of the plant including things like the cell-wall can still be observed.
Some 20,000 years ago during the height of the last glacial maxima in the latter part of the Pleistocene ice age, the Mississippi River drained an ice-gripped landscape far to the north down through what is now Mississippi. Summers brought dark muddy floodwaters down the ancestral Mississippi River as the ice fronts melted back slightly, to then return to a dusty dry floodplain landscape as the next winter and ice returned. High winter winds created large dust storms across the Mississippi River valley and deposited glacial silt along the uplands in Mississippi from Memphis to Natchez and as far east as Hinds County in Mississippi. This silt was ground from the bedrock up north by the flow of ice. This created what is known as the Loess Bluff Region overlooking the Mississippi Delta Region today. The thick mineral-rich loess soils supported a lush temperate ecosystem of grassy plains along older river terraces uplands and hardwoods along stream bottomlands that dissected the region. Megafauna such mammoth, mastodon, giant ground sloths, saber toothed cats, tapir, giant bison, horses, and American lion roamed the area. While more discretely in the grass and forest leaf litter millions of pulmonate gastropods (land snails) thrived along the ground in this thriving ice age environment. Their fossil shell remains are the most abundant and best preserved of any ice-age fossil found in Mississippi. Theses snail shells are around 20,000 years old and perfectly preserved in the loess as if they were deposited yesterday. This specimen was photographed in Natchez last month by Office of Geology staff conducting field geologic mapping for the National Park Service.
Smith County’s geology is crossed by narrow narrow band of limestone hills containing the fossil remains of shallow sea. The band of limestone of the geologic formation called the Vicksburg Group, stretches east from Vicksburg, crosses HWY 18 in Smith County near the Jasper County line, on through Waynesboro, Mississippi.
It is a 30 million year old, extremely fossiliferous geological feature that contains the remains of an entire shallow marine ecosystem that once inhabited what is now central Mississippi from a time called the Early Oligocene epoch.
The limestones are rich with the remains of mostly fossil invertebrates such as mollusks, bryozoans, echinoids, crabs, and foraminifera. It also hosts an amazing variety of vertebrate fossils such as sea turtles, excellently preserved fish, sirenians, rays and sharks…lots of shark teeth!
The Vicksburg Limestone host a great diversity of sharks fossils, both of large and small species. In fact, fossil teeth from Carcharocles auriculatus, one of the largest sharks to ever inhabit the earth have been discovered at these rock outcrops in Smith County.
Featured this week is an excellently preserved fossil echinoid (relative of a sand dollar) named Clypeaster rogersi, from the Mint Springs member of the Vicksburg Limestone. It is surrounded by abundant fossil seashells of the scallop named Pecten byramensis. It was photographed during joint fieldwork being conducted by Office of Geology Staff and other researchers.
Field studies help our scientists understand and familiarize themselves with the geology of the state and study how it related to the stratigraphy and geological history, the environment, mineral and groundwater resources, and to natural and wildlife ecosystems.
Mississippi’s unique geology is endowed with extremely rich fossil deposits. Many of these treasures adorn local personal collections and professional collections in museums across the globe. Though the interest in Mississippi’s geology by collectors and scientists is mainly in these excellently-preserved fossil specimens, our State’s gravels have been regularly combed since ancient times for beautiful stones such as agates, carnelian, jasper, clear quartz, and petrified wood. A Mississippi tradition that today is still held by many rock-collecting enthusiasts. But until recently, no known precious gemstones have ever been discovered in Mississippi.
About a hundred years ago in neighboring Louisiana, a small-scale deposit of gem-quality opal was mined. This occurred in the Flemming Formation of Vernon Parish along the Texas border where a small deposit of vibrantly colored matrix was discovered cementing sandstone into hard quartzite. This opal was once sold directly to Tiffany’s Inc. in New York City and fashioned into gemstones.
Field mapping by the Mississippi Geological Survey in Claiborne County in 2004, has led to the discovery of another precious opal deposit in the South. This time from the Catahoula Formation of Mississippi. This rare occurrence is even more spectacular than the one found in Louisiana.
The research leading to this amazing discovery was conducted under a cooperative geologic mapping grant between the United States Geological Survey and the State. The raw stone material was initially tested for gem quality by the Mississippi Gem and Mineral Society’s expertly skilled craftsmen. The exquisitely-crafted stones show beautifully brilliant flashes of opal fire, ranging in color from green to red.
The discovery of this site is very sensitive, not only for the precious gem-quality opal it contains, but also because of the signs of pre-historic Native American activity associated with the outcrop. This includes opalescent quartzite artifacts! A number of other quartzite-bearing outcrops have been discovered mapping in south Mississippi. Therefore, it is entirely possible that other outcrops may also contain gem-quality Mississippi Opal.
Cauliflower chert geodes, also commonly referred to as “Keokuk geodes”, can commonly be collected from our Pre-loess Terrace gravels and from gravel bars along the Mississippi River. They are typically lined with quartz crystal druse or botryoidal chalcedony, while some examples grew solid and lack a geode cavity. They originated from Paleozoic bedrock limestones in the upper-reaches of the Mississippi River and its tributaries and were carried down here to Mississippi as a constituent of gravel. Many of these cauliflower chert geodes once originated as ancient fossils, such as calyxes crinoid, that became the nucleus for silica mineral growth from fluids within the limestone. The fossil became badly distorted by the growth of chalcedony and remained hollow inside until mineral-rich waters deposited quartz growth along the walls of the badly distorted fossil. The resulting cauliflower chert eroded from the bedrock limestone, leaving pits along its surface where the remaining fossil piece dissolved out. Figured in stages, is this geologic process of cauliflower chert formation recorded in crinoid calyx examples collected from Paleozoic bedrock, along with two cauliflower chert geodes from the Pre-loess Terrace gravels from Mississippi. The last two examples were photographed from Mississippi gravel. The first (stage 4 photo) was collected from Yazoo County and latter, in-situ on the banks of the Mississippi River by MDEQ, Office of Geology staff in Natchez. Special thanks to Rebecca Thea Davis for providing the bedrock fossil examples from Tennessee.
Our chert gravel deposits in Mississippi eroded from ancient limestone bedrock sources north of here, up in the mid-continent, and were brought down and deposited by rivers as they crossed the coastal plain on their way to the Gulf of Mexico.
Patterns of Mississippi’s chert gravel were created by the abundant fossils remains of ancient Paleozoic era sea creatures (hundreds of millions of years old) and spark the curiosity of our local rock and fossil hunters and folks of all ages today. This undoubtedly has also been the case for people here more than 13,000 thousand years.
Towards the end of the last ice-age, the indigenous population of Mississippi first utilized these abundant fossil-bearing chert gravels as a primary resources for tool manufacturing. On literally a daily basis, over the course of thousands of years, these first people’s cultures encountered these patterns created by these fossils preserved in the stone that a familiarity with these gravel fossils surpasses any of today.
Figured in this post is a good example of this in an artifact called a flake, a sharp spall created during a lithic tooth manufacturing technique called flint-knapping. It was collected from a Woodland cultural period site (500BC-1000AD) in a plowed agricultural field by Olivia Anderson in Yazoo County. This example is littered with well-preserved fenestrate bryozoan fossils that were identified in the artifact by Office of Geology staff.
Bryozoans are colonial animals similar to corals but are unrelated. Fenestrate bryozoans can easily be identified by their delicate lace-like structures. These ancient Bryozoans first appeared in the fossil record during the Carboniferous and went extinct during the Permian period (345-268 million years ago). They are one of the most common fossil occurrences amongst our chert gravels.
So what were the stories and traditions about these fossil that the person that made this artifact had? Undoubtedly, this person had an intimate knowledge and an encyclopedic cultural understanding of these gravel resources, as did generation after generation before them in making literally millions of tools from these native geologic resources.
More on our gravel fossils:
Rocks And Fossils Found In Mississippi’s Gravel Deposits – MDEQ
Towards the end of the last ice age, the area that is now the Mississippi’s Loess Bluff region was a strange place some 20,000+ years ago. Frequent dust storms in the Yazoo Basin brought massive amounts of glacial silt off the Mississippi River floodplain. It came down the river from glacial meltwater floods, blown off the surface once dry, and deposited into the adjacent eastern uplands. These thick loess soils are very rich in minerals and nutrients and were quickly vegetated in the moister climate of the bluffs. Several species of giant ground sloths once inhabited this area and thrived eating the lush vegetation in the loess bluffs. They were true gentle-giants. Their fossil bones, such as this exceptionally well-preserved claw found by last month by William Pettis in Yazoo County and identified by Office of Geology staff, are a testament to this lost world from the ice-age in Mississippi’s Loess Bluff region.
Specimens of siderite (an iron carbonate mineral) are among the most common rocks brought in off the Mississippi River for identification. They are unusually heavy for their size and range in color from black to red-orange and typically exhibit very shiny polish on the surface of the stone. They are often mistaken for a variety of things such as meteorites, fossil bones and teeth, and even dinosaur skin impressions due to their wide range of unusual shapes, sizes, and textures. Siderite forms naturally from the geochemistry of the groundwater of the Mississippi River’s alluvium. This mineral can indeed replace (mineralize) organic materials such as fossil bone, wood, and apparently even mollusk shell by occupying tiny pore spaces of these organic materials. One particularly interesting specimen was brought into the Museum of the Mississippi Delta by Laura Sanford during a fossil road show in late October in Greenwood. It was identified by at the special program by Office of Geology staff as a rare occurrence of a Pleistocene age, siderite-replaced freshwater mussel shell from the alluvium of the Mississippi River. This unusual ice-age mollusk fossil was collected on the Louisiana side of the Mississippi River in East Carroll Parish. Geology staff identified it as Potamilus purpuratus, also commonly known as Bluefer or Purple-shell mussel, aptly named for its distinctive beautiful purple color mother-of-pearl of this species, which still inhabits many rivers in Mississippi and Louisiana today. The excellent presentation of this fossil freshwater mussel exhibits both valves of the shell still articulated (attached) in typical mussel death position (shell open).
This week, just minutes after MDEQ’s Surface Geology staff Jonathan Leard successfully defended his masters thesis at Mississippi State University on the first detailed geologic map of the Starkville area, he was found studying an important and newly exposed geologic outcrop just off of campus. Here he explains to MSU freshman anthropology student, Abigail Starnes the important geologic contact that is represented in the fresh excavation. The lighter-colored rock unit below, is a limestone called the Prairie Bluff Formation. It from the Late Cretaceous period and is chock full of marine sea shell fossils that were some of the last things alive in the ocean just before the meteorite struck the earth that killed off the dinosaurs some 66 million years ago. The darker-colored deposits above the limestone are significantly younger and are from the late Pleistocene. It contains the fossilized remains of extinct ice-age land animals that the first people in North America and the first Native Americans to arrive here in Mississippi would have encountered. The contact between these two geologic units is called an unconformity because it represent missing time between the two formations. In this case, a hiatus of tens of millions of years, which can only demonstrated by studying the abundance of different fossils contained between the two geologic units at this outcrop.
The current near historic low of the Mississippi River has it’s dry banks exposing miles of seemingly endless sandbars that are now, once again, sharing its ice-age secrets from the river’s depths. Pleistocene fossils from extinct beasts such as American lion, giant bison, mastodon, saber toothed cats, horses, giant ground sloths, tapir, gomphothere, pampather, and dire wolves that once hunted and grazed along the forests and wetlands of the Mississippi River floodplain have now been exposed along the now barren river bottoms. Surface Geology staff joined the Mississippi Museum of Natural Science and USFWS scientists this week along the banks of Mississippi River in Warren County to help understand and to better document these important paleontological resources during this unique environmental opportunity.
During this field trip an important discovery of a fossil of an ancient bear-sized rodent, a giant beaver called Castoroides ohioensis, was made by biologist Paul Hartfield during the trip. Paleoindian cultures, the first human inhabitants of Mississippi, likely shared their environment with this and other strange Mississippi ice-age beast.
Additionally, a larger ice-age Mississippi River bottomland ecosystem was documented during the study which included fossils of giant catfish, gar, turtles, alligators, giant bison, deer, elk, mastodon, mammoth, and horse. These fossil specimens will be accessioned into the Mississippi Museum of Natural Science paleontological collections for public display and for scientific study.
As the glacial climate ended and the environment rapidly changed along the Mississippi River at the close of the Pleistocene, the ice-age megafauna gradually became extinct. People persisted along the great river and they, along with the ecosystem began to adapt to a world that we are more familiar with today.
The first people, to inhabit the Mississippi’s Northwest Delta region towards the end of the last ice age lived in quite an unfamiliar world than that of today. It was once thought that this area, known today as the Yazoo Basin, was an environment called as “braided stream”, a formidably unstable landscape that would have been largely uninhabitable by these first people known as Paleoindian cultures.
This idea was only just recently dispelled by research that identified numerous Paleoindian archaeological sites and used it to date landforms within the Yazoo Basin. This important research was published on by a team of scientists from the Office of Geology and the L.B. Jones Trust. The L.B. Jones Trust is an important archaeological and paleontological collection housed at the Museum of the Mississippi Delta for the preservation of Mississippi Delta history and scientific research. View the Office of Geology publication here.
As glacial ice was making its final retreat into the arctic, these ice age Paleoindian hunters here in the lower Mississippi River valley encountered a bounty of wildlife along the meanders and back swamps of the great river. Familiar to these first people of the Delta were animals such as American lion, giant bison, mastodon, saber toothed cats, horses, giant ground sloths, and dire wolves that hunted and grazed along the forest and wetlands of the Mississippi River floodplain. As the climate rapidly changed at the close of the Pleistocene and the megafauna gradually became extinct, people in the Delta during the Early Archaic cultural period adapted to their surroundings.
Remains such as fossil bones and teeth of these extinct ice-age beasts that once inhabited the Delta can still be found along the gravel bars of the Mississippi River today. Featured in this week’s fossil Friday is the portion of a fossil jaw from bear-sized ground sloth, Paramylodon harlani, commonly known as Harlan’s ground sloth. It was collected in Washington County, Mississippi by L.B. Jones Trust chairman and researcher, Anna Reginelli and identified this week by Office of Geology Staff.
As geology is the basis for the environment, geology staff is often involved in multidisciplinary research with other agencies and institutions. Yesterday, Geology staff assisted the Mississippi Museum of Natural Science conservation biology team in a freshwater mollusk survey being conducted on the Pearl River in Marion County. During Thursday’s survey, State Ichthyologist, Robbie Ellwanger discovered a bone from a very large turtle amongst the gravel in the river. The bone was identified by geology staff in the field as an ice-age fossil turtle and the specimen was collected for study. Vertebrate fossils from this part of Mississippi are very rare and are essential to our understanding of the geologic history of the area. Once the team returned to the museum, Paleontologist George Phillips further identified the fossil bone as a piece of a large alligator snapping turtle shell. This find is a first for the area, making it an important contribution to the fossil record.
The alligator snapping turtle (Macrochelys temminckii) is the largest species of freshwater turtle in North America. Individuals of this icon reptile can live over 100 years and grow to be more than two hundred pounds. The family that includes these turtles goes back to the days of the dinosaurs during the Cretaceous period. Very little is known about alligator snapping turtles in the fossil record and most material available for study comes from ice age river and swamp sediments deposited during the Pleistocene. They are currently listed as a vulnerable species in need of conservation efforts. This important fossil specimen will be accessioned into the Mississippi Museum of Natural Sciences paleontological collections. There, it will help scientists to better understand the Pearl River’s ancient geologic past and will also help in studies of this living fossil in North America.
Mississippi’s wealth of well-preserved fossils have been studied by researchers from all over the world for more that two centuries. That tradition continues through to today as MDEQ,s geologist performs the work of Mississippi’s Geological Survey in studying the state’s natural resources and its natural history. The fossils contained in the various geologic deposits around the state hold important clues to past life, past climates, and past ecosystems. What our scientists learn has implications for not just here in Mississippi but also around the world. Fossils are important tools for geologists to help map geologic formations and to correlate rock units far beyond the boarders of the state. The scientific value of invertebrate fossils such as ancient marine mollusk shells are very important in this respect. Our State Geologist, Dr. David T. Dockery is an invertebrate paleontologist who’s research focuses specifically on studying, naming, and describing these important resources. Following recent publications on hid studies of fossil mollusks from the Late Cretaceous deposits of northeastern Mississippi, 27 holotypes of new fossil gastropod species were sent to the Smithsonian this month to be archived in the U. S. Natural History Museum’s collections.
This Late Archaic cultural period Native American artifact, utilized as hammer-stone, was collected off a prehistoric archaeological site by an oxbow lake near Satartia in Yazoo County, Mississippi. It was utilized sometime between 2,000 BC and 800 BC from a large Stromatoporoid chert gravel fossil.
Stromatoporoids were reef-forming sponges from the Devonian period (some 400 million year old). They are found among the gravels of ancestral Mississippi River Pre-loess Terrace Deposits, beneath the loess along the western bluff line overlooking the Mississippi River Delta region, from Memphis to south of Natchez. Their natural presence and abundance in these Pre-loess Terrace gravels helps to mark a geologic shift in drainages of the exposed bedrock sources in the upper reaches of the Ohio River Valley region during glaciation of the mid-Pleistocene some 700,000 years ago.
They are curiously absent from our older (pre-glacial) Pliocene age High Terrace gravels further east in south-central Mississippi. The occurrence of these chert fossils in archaeological context at sites has been observed broadly across the MS Delta Region and also, as far east of the bluff-line as Smith County in Mississippi. This helps demonstrate a relatively long distance prehistoric cultural trade of these high-quality, larger chert clast-size gravel resources that emanated from the Mississippi loess bluffs region, east into areas with limited and poorer quality available resources.
Special thanks to Jim House of the Mississippi Archaeological Association, Madison Chapter for allowing MDEQ, Surface Geology staff to identify and photograph this remarkable fossil artifact specimen.
Linked below is the MDEQ FossilFriday post from September 6, 2019 featuring another interesting stromatoporoid fossil culturally utilized as an ancient artifact. It is polished mano artifact collected from an archaeological site along the Leaf River in Smith County, Mississippi. This was found roughly 100 miles east from its original natural source in the Loess Bluffs. The use-wear exhibited on the mirror-like, highly-polished surface of the artifact exposed incredibly detailed features of the fossil’s mamelon and astrorhiza structures.
Click here to learn more about the Smith County Stromatoporoid Artifact Specimen:
The revelations garnered from our recent geological mapping work on the timing and evolution of the lower Mississippi River Valley, has lead to the development of a new framework to better understand the environmental effects of the cyclical glaciation on the lower Mississippi River valley and it’s geology. Our work has identified Pleistocene deposits containing a host of well-preserved flora, faunal, and even early cultural remains that have yet to be fully studied and relayed in their proper context.
Core samples were taken today during a drilling projects to study an uninterrupted stratigraphic section of an ancestral Mississippi River Pre-loess Terrace Deposits in Jefferson County, MS. This terrace is blanketed by more than 70 feet of loess cover, masking a perfectly-preserved paleosol and surfacial clay stratum from the alluvium of the ancestral Mississippi River during the last interglacial stage of the Pleistocene. This is just before the river abandoned this level and began cutting its present valley during the last glacial advance.
Radiometric dating of these core samples is planned and will necessarily benefit our stratigraphic understanding along. Palynological research for paleoenvironmental context will be done, as well.
Outcrops of this terrace have been described along the river in the early literature as the “Natchez Formation” but the extent and context of it has only been recently understood. We have mapped the extent of this level of Pre-loess Terrace from southern Claiborne to Adams County.
The expression of this loess-draped terrace surface is heavily dissected today by erosion. But during the last glacial episode, it hosted a lush broad and level prairie environment overlooking the Mississippi River and boarded to the east by the older aggressive uplands.
Thanks to the work of George Roberts, a host of well-preserved late Pleistocene Megafauna remains have been recovered from the drainages that dissect this feature along with artifact evidence of early habitation from Paleoindian and early archaic cultures. Undoubtedly this is just scratching the surface of what is preserved here.
Within the last few thousand years this feature has undergone erosion, but still was was considered ideal for habitation into the later cultural periods. Iconic archaeological sites such as Feltus Mounds, Anna Mounds, Windsor Mounds and Windsor Ruins are just a few of studied sites adorning the expression of this terrace surface. — with Paul Parrish and Jonathan Leard.
Geology is the basis for the environment and fossils are an important tool for our scientists that study Mississippi’s geology. These ancient clues provide us the necessary details to understand the age, depositional environments, and layered sequences that make up the geology of our state. Many people think of Mississippi’s fossils as the large ancient bones and numerous sea shells which can been found throughout the state. But many of the most important fossils we study can’t be seen with the naked eye. Billions of tiny skeletons of animals called foraminifera make up much of our state’s limestones and other marine deposits while tiny grains of fossil pollen and spores from ancient plants can be quite abundant and exceptionally well-preserved in many of our terrestrial deposits. Studying these sequences of alternating terrestrial and marine environments helps us to understand past climates and how it has changed over geologic time. While much work has been done on our marine fossils, comparatively little is known about these fossils from our terrestrial environments. Over the past decade, MDEQ’s Surface Geology and Mapping program has been collaborating with a number of universities and institutions to better understand these terrestrial environments and the fossil plants and animals they contain. This team includes researchers from Delta State University, The Smithsonian Intuition, University of South Alabama, Mississippi Museum of Natural Science, University of Southeastern Mississippi, and many others. Recent work has been focused on the plant fossil of the Lower Oligocene age Forest Hill Formation while sampling several outcrops during geologic mapping across the central part of the state. The contact between terrestrial Forest Hill Formation and underlying marine deposits of the Late Eocene age Yazoo Clay mark an important boundary in earth’s climate history, some 34 million years ago. The earth had been in a tropical greenhouse environment for tens of millions of years, going back to the days of the dinosaurs, and then suddenly began to cool at the close of the Eocene epoch. This climate shift is recorded in the fossils in both the Eocene and Oligocene age rocks of Mississippi and studying it is important to furthering our understanding of this time period. Preliminary research findings of the palynology (tiny fossil plant pollen and spores) from our sampling efforts of Forest Hill Formation were presented in a poster by our study’s lead author from Delta State University, Dr. Nina Riding last month at the Botanical Society of America’s conference in Anchorage Alaska. Surface Geology staff is proud to be a part of this research team. These collaboration efforts in various aspects paleontology continue to expand our understanding of Mississippi geologic past.
To learn more about Mississippi’s Geologic past here.
To learn more about Mississippi’s Cretaceous Geology here.
Do you have a rock or fossil that you want more information on? Click here to Ask a Geologist.
Humans entered the paleontological record in Mississippi at some point during the last ice age. The Native Americans that first arrived in Mississippi encountered an environment that would seem quite strange to us today. The plants of the forests and prairies would be more familiar to modern northern climates than to those of Mississippi today. The landscape hosted animals that are now long extinct such as mastodon, mammoth, giant beavers, ground sloths, horses, and giant bison. These animals were hunted by predators such as saber-toothed cats, dire wolves, and these first peoples. Lower sea levels exposed land far into the Gulf of Mexico miles beyond the barrier islands of today as evidenced by the Office of Geology Mapping in Jackson County, MS as well as an ice-age forest exposed by Hurricane Ivan in 2004, 60 feet beneath the Gulf of Mexico, south of Gulf Shores, AL.
Geology is the basis for the environment and an integral part of archaeology. Geologic mapping is essential to understanding the age of landscapes and their paleoenvironments, as well as characterizing depositional environments and the geochemistries conducive to the preservation of these important archaeological resources. The tools these first people left behind in Mississippi are the only evidence we have to study and learn about these first peoples’ relationship with their environment.
These ice-age cultures are known collectively as Paleoindian. They were thought to be highly specialized and nomadic hunters as evidenced by their exquisitely made tools and the scarce number of longer-term occupation sites that they left behind. The discoveries of most known early Paleoindian artifacts are by landowners, collectors, and hobbyists, and not made by researchers in the field. This makes the general public, those who have found and collected these artifacts, the most important resource for information scientists have to study this early time period in Mississippi’s prehistory.
On June 14, 2022, a very important discovery was made of an early Paleoindian point in Perry County, Mississippi by Matthew Sullivan, an artifact enthusiast and Circuit Court Judge for the 13th District of Mississippi while he was rock and artifact collecting with his friends. Realizing the significance of his find, Judge Sullivan brought it to the attention of the Surface Geology staff for examination. Retired archaeologist, Samuel Brookes consulted on the find during Judge Sullivan’s visit. The artifact was identified as a Clovis point making it approximately 13,000 years old. Geology staff identified the stone as a rare form of pure chalcedony not naturally occurring here in Mississippi.
Geology staff collected additional laboratory data on the point and consulted with geological surveys in nearby states to conclude the bedrock origins of the stone. The Judge Sullivan Clovis was manufactured from a type of pure chalcedony from agate replacement of fossilized coral. It is an extremely high-quality, translucent stone found only in Miocene and Pliocene age rock outcrops in Florida.
Geological resources naturally available to prehistoric cultures for stone tool manufacturing in the part of southeast Mississippi that The Judge Sullivan Clovis was found are scarce according to recent research published by Office of Geology staff. The discovery of The Judge Sullivan Clovis is important to science because it demonstrates the movement of people and material from east to west through south Mississippi during this ancient time in Mississippi’s ice age history.
Mississippi has a rich geologic past with a fossil record that includes a history in the Mesozoic era, also better known as the days of the Dinosaurs. Outcrops from the Late Cretaceous period underly the rich soils of the Black Prairie and uplands of the Pontotoc Ridge physiographic regions of northeast Mississippi. Much of these deposits were formed in warm tropical shallow seas teaming with life and now rich with their fossil remains. While the dinosaurs walked on land, giant marine reptiles and sharks ruled these ancient seas. Fossil bones and teeth of these animals are commonly found along an abundance of ancient sea shells from mollusks in most outcrops of Cretaceous age in Mississippi. The currents, waves, and storms along with scavengers tend to widely scatter these remains. Therefore, actual fossil skeletons of these animals are important and rare finds. Last month, Surface Geology staff partnered with vertebrate paleontology staff at the Mississippi Museum of Natural Science, to excavate an intact skeleton of a sea dragon, called a Mosasaur. The recent discovery was made by museum staff conducting fieldwork near Westpoint, Mississippi. This species of Mosasaur, known as Clidastes propython, is approximately 80 million years old. Though typically only isolated bones and teeth are ever found, this is the most common mosasaur found between the geologic units of the Tombigbee Sand and the Arcola Limestone at the top of the Mooreville Chalk/Formation. This find was in the middle part of the Mooreville Formation above an important geological mapping marker that can be traced a long distance, a fossil bed made up entirely of the extinct oyster called Ostrea falcata. The team managed to excavate portions of the skull (with teeth still intact) along with a number of vertebrae and some rib bones. This important specimen will be carefully reconstructed and curated for future study. #fossilfriday
During the last ice age, the prairie regions of northeast Mississippi were an environment that was a paradise for a host now extinct Pleistocene mammals and other ice age megafauna. Gently rolling grasslands were once broken by streams with broad alluvial plains boarded by bottomland forests. Saber-toothed cats, American lions, giant ground sloths, mammoths, mastodon, giant bison, giant armadillo, giant elk, giant tortoises, and even herds of horses once roamed this rich dark soils region. Paleoindian cultures, such as Clovis were among the first human inhabitants to Mississippi, some 14,000+ years ago, and were certainly witness to these great animals of long ago and exploited the bounty of this Mississippi ice-age ecosystem. Fossil bones of many of these extinct animals are commonly found in stream alluvium of the Black Prairie region of northeast Mississippi. Pictured is a large unidentified ice-age fossil mammal bone exposed along an outcrop of Pleistocene age stream alluvium that was encountered by MDEQ, Surface Geology staff while conducting field work this week in Clay County with the Mississippi Museum of Natural Science while studying the underlying Cretaceous geology bedrock. The natural weathering of these chalky limestones over the course of tens of thousands of years form the dark rich soils for which is the basis for this prairie environment.
The last days of the dinosaurs ended some 66 million years ago when a giant meteorite impacted the Gulf of Mexico and created a world-wide extinction event which instantaneously changing Earth’s environment, climate, and devastated ecosystems. As the work of the State’s Survey, research is being conducted by MDEQ’s Office of Geology staff this week in the Starkville area to map and delineate geology representing this time. This will be used to better understand this important time in Earth’s history, both before and after this event, which is best recorded in our geologic record in northeast Mississippi. Featured here are Late Cretaceous marine fossils from the Prairie Buff Formation that are being studied by our scientists from outcrops in Starkville area. Fossils from this time not only include the infamous dinosaurs, but also important invertebrate fossils, part of a once thriving diverse tropical marine ecosystem. This is represented in the Prairie Buff Formation by an abundance of giant extinct fossil oysters, clams, and snails that once inhabited the sea floor of the during the Late Cretaceous, just moments before the extinction event. #fossilfriday
Gravel fossils are many Mississippi folk’s (especially children) first exposure to paleontology. These ancient tiny fossil treasures can commonly be found along gravel roads and driveways, along creeks and streams, even on school playgrounds throughout much of Mississippi. Seven year old Fen Anderson, a budding geologist from Yazoo County, recently shared his discoveries with MDEQ, Office of Geology scientists. These tiny ancient sea creature fossils are of solitary rugose corals and crinoid stems from Paleozoic era, making them older than the days of the dinosaurs. His awesome fossil collection pictured here came from just one day’s worth of searching through playground gravel at Manchester Daycare. #fossilfriday
For more on collecting rocks and fossils from Mississippi gravel, click here.
Ichnology is a discipline of Paleontology that is the scientific study of tracks and trace fossils. Knowing what kinds of animals occupy certain depositional environments, the traces and tracks they leave behind, and an understanding of geochemistry help us to translate ancient geologic outcrops. This beautiful example was collected in Lauderdale County by Leslie Potter and sent to Office of Geology staff this week for identification through our “Ask a Geologist” online public outreach program. These excellently-preserved fossil decapod burrows are part of the Lower Eocene age Tallahatta Formation. This ichnofossils is named Thalassinoides and were made by numerous marine burrowing shrimp that once occupied a tropical sandy shallow sea floor that once occupied the east-central Mississippi area some 50 million years ago. They are preserved as stone casts from being naturally cemented with silica minerals that have now become harder than the surrounding sandstone so that they weather in relief. Because the chemistry of the sediments didn’t preserve any other fossils of marine life that once certainly occupied the area, these ichnofossils prove important to helping us understand the ancient depositional environment of the sandstones of the Tallahatta Formation. Every so often some rare fossil sea shell impressions have been found there but are extremely rare, whereas these Thalassinoides burrows are quite abundant. This one in particular is a pretty special find. The gassy-fill substance in the burrow is called Tallahatta Agate. It is a natural mineral formation of nearly pure chalcedony and opaline silica. Thank you again Leslie Potter for sharing your discovery with our geology research staff and allowing us to share it with others.
Click here to learn more about Lauderdale County geology
Ancient marine fossils, much older than the days of the dinosaurs can be found in chert gravels right here in Mississippi. This crinoidal chert (a type of rock that was once the sea floor dominated with the skeletal remains of fossil crinoids) from Jefferson County was photographed this week by Office of Geology staff. Complete fossils of crinoids are rarely preserved intact, though there individual segments and partial stems and calyx are some of the most common chert gravel fossil found in Mississippi. Crinoids are echinoderms, relatives of starfish and sand dollars and are still alive today in the worlds oceans. Paleozoic era chert gravel fossils from Mississippi can be found naturally though much of the state. They were once eroded from ancient limestone bedrock sources north of here, up in the mid-continent, and were brought down and deposited by by ancient rivers flowing to the Gulf of Mexico. Collecting gravel fossils are often the first exposure folks have to our rich paleontology resources in Mississippi. Crinoids are one of the many treasures to be found in our Mississippi chert gravels. Chert gravels is an important economic resource commonly used in many civil applications throughout Mississippi. So, gravel fossils can be found almost anywhere from playground, aggregate, to gravel roads and driveways, even in cement gravels along downtown sidewalks.
Click here for more information on Mississippi gravel fossils.
Calcite septarian nodules (commonly called dragon stones) are natural concretions of calcium carbonate that exhibit secondary mineral growth of yellow “dog-tooth” calcite along an intricate network of desiccation-like cracks. They make excellently beautiful mineral specimens, especially when they are carved, cut, and polished or as interesting curiosities if left natural. They typically form in impure, sandy, and fossil shell-rich limestones (called marls) from the geochemistry and movement of shallow groundwater. Groundwater moving through the marl formation derives carbonate minerals from dissolving and leaching from fossil sea-shells in the rock and concentrates it into a nodule. As the nodule solidifies to a hard rock it begins to shrink and a network of cracks form throughout the nodule. The voids created by the desiccation-like cracks then begin growing “dog-tooth” yellow calcite mineral precipitated from the carbonate-rich groundwater water. These nodules are much harder and more erosionally-resistant than the surrounding geologic formation they formed in. Therefore, they tend to weather in relief from the outcrop or completely weather out and can concentrate as unusually large bolder-gravels along stream beds that wind their way through the formation. Only a few geologic formations in Mississippi exhibit this phenomenon. Most notably is the early Eocene age Bashi Formation of east-central Mississippi in the vicinity of Meridian. Another example (photo below) of exceptional quality was recently documented by MDEQ, Office of Geology staff from the Late Eocene in age Moody’s Branch Formation while describing geologic outcrops in the field with in Yazoo County, Mississippi.
Click here for more on Mississippi’s Geologic past.
Ichnology, a discipline of Paleontology, is the scientific study of tracks and trace fossils. Knowing what kinds of animals occupy certain depositional environments, the traces and tracks they leave behind, and an understanding of geochemistry help us to translate ancient geologic outcrops. These excellently-preserved fossil decapod burrows where photographed in the field last week by MDEQ, Office of Geology staff. The fossil burrows were discovered eroding from an Eocene (Claiborne age) outcrop of the Creola Member of the upper Cockfield Formation exposed in the creek floor. They are preserved as stone casts from being naturally cemented with siderite, a distinctive iron carbonate mineral. Siderite commonly forms in shallow marine, brackish water, near-shore environments. With these clues found in the outcrop in the floor of the creek along with numerous seashell fossils it contains, it’s not hard to imagine a place very much like the Mississippi Sound today…shallow muddy water filled with burrowing crab and shrimp, as well as snails, oysters, and clams while drum fish, sea trout and flounder tail along the grassy shallows…but this is almost 40 million years ago, in a world filled with much more stranger beasts…and in Yazoo County, Mississippi. #fossilfriday
