24R: Houston County, Georgia
Fossils Location Explanations
By Thomas Thurman
13/April/ 2025
General Houston County Stratigraphy.
- Assorted residuum
- Northern parts of the county have assorted residual deposits spanning from Cretaceous to Miocene with no observable fossils that I have seen.
- This changes at a line roughly represented by Hwy 96 spanning east to west in the county, beneath this line recognizable formations and fossils exist.
- Early Oligocene residuum (chert) Appo. 33 million years ago
- Abundant in many parts of southern Houston County, as boulders, dornicks (hand samples), to thumbnail samples.
- Often uncovered and relocated during road construction and farming. So road cuts are worth inspecting.
- Often found where streams have incised the terrain.
- Eocene/Oligocene boundary
- Observable extinct event 33.9 million years ago
- Ocmulgee Formation/Tobacco Road Sand Formation
- Uppermost Eocene 34 million years ago
- Twiggs Clay of varying thickness
- Upper Eocene 34 million years ago
- Tivola Limestone
- Upper Eocene 35 million years ago
- Clinchfield Sand (rarely exposed)
- Upper Eocene, 35.5 milli0n years ago
- Gap, Unconformity
- Huber Formation (West side of Houston County)
- Appo. 60 million years ago
PLEASE DO NOT TRESSPASS
All listed locations have been
confirmed by the author.
The above map is available as a download at the base of this page.
All listed locations have been
confirmed by the author.
The above map is available as a download at the base of this page.
1; Elko Rd Tivola Limestone Quarry
Can be seen on both sides of Elko Rd. Exposures on the west side are undisturbed and are weathered black. The main deposit is eastward all the way to Hwy 224 as a series of quarries at the base of the Ocala Escarpment. In 1932 this site produced a large early whale (Basilosaurus cetoides) which was collected by
Wesleyan College and current hangs in the Smithsonian.
(See page 14C of this website)
Can be seen on both sides of Elko Rd. Exposures on the west side are undisturbed and are weathered black. The main deposit is eastward all the way to Hwy 224 as a series of quarries at the base of the Ocala Escarpment. In 1932 this site produced a large early whale (Basilosaurus cetoides) which was collected by
Wesleyan College and current hangs in the Smithsonian.
(See page 14C of this website)
2,3, & 4; Abandoned, but un-reclaimed, Tivola Limestone (Eocene) quarries. Former quarries, Private property
5; Active Cemex Tivola Limestone Quarry
Also quarrying Twiggs Clay and limited Clinchfield Sand.
Also quarrying Twiggs Clay and limited Clinchfield Sand.
6: Early Oligocene Residuum as boulders and dornicks in the road cuts on both east and west sides of Elko Rd, often rich in shelly fossils, abundant material easily collected.
7: Twiggs Clay & Ocmulgee Formation (Latest Eocene) outcrops in roadcut on the eastern end of Oaky Woods Access Rd, fossil present but rare. I have screened the Twiggs from the roadcuts and found small shark & fish teeth.
8: Latest Eocene Tobacco Road Sand overlain as an unconformity with Early Oligocene Residuum (as boulders and dornicks) in
ravines and on forest floor just south of this turn on Oaky Woods
Road. Periarchus sand dollars present in the Tobacco Road Sand.
Gastropods and clams present in the Early Oligocene Residuum.
The unconformity exists as the Oligocene Residuum was once a
Early Oligocene limestone bed, parts of which became silicified
into chert and the rest weathered (dissolved?) away leaving the
Oligocene material suspended in red clay of uncertain age.
(See Page 14N of this website.)
ravines and on forest floor just south of this turn on Oaky Woods
Road. Periarchus sand dollars present in the Tobacco Road Sand.
Gastropods and clams present in the Early Oligocene Residuum.
The unconformity exists as the Oligocene Residuum was once a
Early Oligocene limestone bed, parts of which became silicified
into chert and the rest weathered (dissolved?) away leaving the
Oligocene material suspended in red clay of uncertain age.
(See Page 14N of this website.)
9: Staircase Stream, Latest Eocene Tobacco Road Sand overlying Twiggs Clay. This is a rain fed stream creating a series of steps and ravines as it incises the hill side. At top is a deepish Tobacco Road Sand ravine where fragmentary Periarchus sand dollars occur in the walls. As the flow transitions to the Twiggs clay beds of limestone, sometime highly fossiliferous, occur in the Twiggs Clay. Shark teeth have been observed. It is illegal to remove fossils from wildlife management areas, collection by photography only please. See page 14N of this website.
10: Cliff Faces. At end of this access road is a parking clearing on a forested hilltop. Head north through the woods and you’ll soon see Early Oligocene chert boulders and rocks stacked from when the area was cleared for farming. Many of these rocks have fossils. Continue north and downhill for .5 mile (?) and upon reaching the valley floor look eastward along the hill and you’ll see a series of Ocmulgee Formation cliffs rich in fossils. See Page 14N of this website.
11: Colonial bryozoans from the Ocmulgee Formation (uppermost Eocene) occur naturally on a hillcrest in Oaky Woods as often pristine, nearly golf-ball-sized, colonies. Oligocene and Eocene fossils occur in several places in Oaky Woods, very frequently in ravines and or hilltops. They can be difficult to predict. See Page 14N of this website for details
12: Shell fossils, shark teeth, and a partial entelodont tooth (probably early Oligocene) recovered from an overburden mound across Robert Bryson Smith Parkway just south of Hilltop Elementary. The mound was created during school and neighborhood construction. This was the second entelodont tooth found and Georgia, but it has since been lost during shipping from one university to another. See this website page 16 for details.
13: Shelly Early Oligocene fossils as hard chert were uncovered and occur abundantly during construction of this neighborhood. This includes neighborhoods around Robert Bryson Smith Parkways. Look at lower elevations and between hills.
Such fossils are common in many parts of southern Houston County, they have no been studied, to my knowledge, in many decades. No vertebrate material has been reported from these rocks, sharks, probably whales and manatees or dugongs were certainly present, but their fossils have never been identified. It has been suggested that their fossils dissolved in the solution which created the cherty rocks. See Page 15C of this website.
Such fossils are common in many parts of southern Houston County, they have no been studied, to my knowledge, in many decades. No vertebrate material has been reported from these rocks, sharks, probably whales and manatees or dugongs were certainly present, but their fossils have never been identified. It has been suggested that their fossils dissolved in the solution which created the cherty rocks. See Page 15C of this website.
14: Early Oligocene residuum occurs as boulders and dornicks, shell fossils common. See Page 15C of this website.
15: Early Oligocene fossils occur in road cuts in many places along Hwy 26, especially where streams have incised shallow valleys, large boulders and slabs occur.
16: Late Eocene Tivola Limestone fossils occur beneath RR bridge over creek. See Page 14C of this website.
17: In Bonaire, undescribed (unnamed) limestone debris naturally occurs along highway 247 within the southern ramp access circle to eastbound highway 96. This limestone was once a larger deposit but was disturbed during ramp construction. Not densely fossiliferous, but fossils do occur, bryozoans, rare
Periarchus echinoids, and turritella casts were observed by this author. There is a bridge crossing a railroad track immediately west of this location and the limestone appears there as well. In 1911 (Veatch & Stephenson) reported a whale fossil (Basilosaurid) from a railroad cut .25 miles north of the Bonaire, GA railroad station. This would the same location and limestone. This limestone was also observed further west on Hwy 96 near Old Perry Road, on the north side of Hwy 96 at Houston Family Care at Bonaire. There are several limestone boulders used as erosion control at a culvert near the road. It holds far less bryozoan material and fossils in general than the Tivola Limestone, is generally smoother in texture and harder. So it seems distinct from the Tivola. This exposure was shown to Paul Huddlestun in 2012, Huddlestun named most of the Eocene exposures in Central Georgia, but he could not identify and stated that he had never seen it before.
Periarchus echinoids, and turritella casts were observed by this author. There is a bridge crossing a railroad track immediately west of this location and the limestone appears there as well. In 1911 (Veatch & Stephenson) reported a whale fossil (Basilosaurid) from a railroad cut .25 miles north of the Bonaire, GA railroad station. This would the same location and limestone. This limestone was also observed further west on Hwy 96 near Old Perry Road, on the north side of Hwy 96 at Houston Family Care at Bonaire. There are several limestone boulders used as erosion control at a culvert near the road. It holds far less bryozoan material and fossils in general than the Tivola Limestone, is generally smoother in texture and harder. So it seems distinct from the Tivola. This exposure was shown to Paul Huddlestun in 2012, Huddlestun named most of the Eocene exposures in Central Georgia, but he could not identify and stated that he had never seen it before.
18: Sassafras Hill Quarry (private property), Huber Formation (?) appo. 60 million years, plant material, leaves, twiggs, biologic debris. Location has not been properly studied and there is likely pollen present which could accurately date deposit. See this website page 9B; Sassafras Hill Quarry.
19: Twiggs Clay or Ocmulgee Formation, Late Eocene. In the stratigraphic column the Ocmulgee Formation limestone overlies the Twiggs Clay. Twiggs Clay has limestone beds, but they are typically rare. Paul Huddlestun, who described and named the Ocmulgee Formation, says clay is rare to absent in it. Across Hwy 247 from the main entrance to the Houston County Landfill (west side of road) in southernmost Houston County is a hill of clay rich limestone which could be Twiggs Clay or Ocmulgee Formation, fossils are present but they are few. Continuing south on Hwy 247 dense limestone ledges, several feet thick, occur on the east side of the road for at least .5 mile south of the landfill main entrance, fossils are rare. The Ocmulgee Formation limestone is typically rich in fossils, where Twiggs Clay limestone beds are usually sparsely fossiliferous. For this reason, I suspect these limestone ledges are Twigg Clay.
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Houston Co. Fossil Map available for download to right.
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