Alachua Formation facts for kids

Quick facts for kids Alachua Formation Stratigraphic range: Early-Late Miocene (Hemingfordian-Hemphillian) ~20–5.3Ma PreЄ Є O S D C P T J K Pg N
Type	Formation
Lithology
Primary	Claystone, sandstone
Other	Phosphorite
Location
Coordinates	29°42′N 82°36′W / 29.7°N 82.6°W / 29.7; -82.6
Approximate paleocoordinates	29°48′N 80°54′W / 29.8°N 80.9°W / 29.8; -80.9
Region	Florida
Country	United States
Type section
Named for	Alachua, Florida

The Alachua Formation is a special geologic formation found in Florida. It's like a giant time capsule! This rock layer was formed during the Miocene period, which was about 20 to 5.3 million years ago.

The Alachua Formation is made up of different types of rock. These include claystone (like hardened clay), sandstone (like hardened sand), and phosphorite. Phosphorite is a rock rich in phosphorus, which is important for plants and animals.

What makes this formation so cool is the amazing number of fossils it holds. Scientists have found many ancient animals here. These include mammals, birds, reptiles, and fish. Even the teeth of the giant megalodon shark have been discovered!

What Kind of Fossils Are Found Here?

The Alachua Formation is famous for its incredible collection of ancient life. It helps us understand what Florida was like millions of years ago.

Ancient Mammals

Many different kinds of mammals once roamed the land where Florida is today. The Alachua Formation has preserved their remains.

Rodents and Small Mammals

• Harrymys magnus and Nototamias hulberti are examples of ancient rodents.
• Scientists have also found fossils of bats (Chiroptera indet.) and moles (Talpidae indet.).

Meat-Eating Mammals (Carnivores)

The formation holds fossils of many ancient predators.

• Large dog-like animals like Amphicyon longiramus and Epicyon haydeni once hunted here.
• There were also ancient weasels (Sthenictis sp.) and even early cats (Felidae indet.).

Giant Ground Sloths

Imagine sloths as big as bears!

• Pliometanastes protistus and Thinobadistes segnis were huge ground sloths. They were very different from the tree sloths we see today.

Elephant Relatives (Gomphotheres)

These were ancient relatives of elephants, with long tusks.

• Amebelodon (Konobelodon) britti is one example. Some had shovel-like tusks!

Hoofed Animals (Artiodactyls and Perissodactyls)

Many hoofed animals lived in this ancient landscape.

• Artiodactyls include animals with an even number of toes, like ancient camels (Aepycamelus major) and deer-like creatures.
• Perissodactyls have an odd number of toes, like ancient horses and rhinos.
  • Many types of ancient horses have been found, such as Calippus elachistus and Nannippus morgani.
  • Ancient rhinos like Teleoceras proterum also lived here.

Sea Cows (Sirenians)

Even marine mammals are found!

• Metaxytherium cf. floridanum was an ancient sea cow, similar to today's manatees.

Ancient Birds

The Alachua Formation also gives us a peek into the ancient bird life of Florida.

• Fossils of ancient cormorants (Phalacrocorax wetmorei) and ducks (Anatidae indet.) have been discovered.
• There were also ancient hawks (Promilio brodkorbi) and even a type of roadrunner (Thomasococcyx philohippus).

Ancient Reptiles

Reptiles were a big part of the ancient ecosystem.

Turtles

Many types of turtles, both land and water dwellers, are found.

• Giant tortoises like Hesperotestudo turgida once roamed the land.
• Ancient snapping turtles (Macrochelys auffenbergi) also lived in the waters.

Crocodiles and Alligators

Florida has always been home to large reptiles.

• Fossils of ancient alligators, including Alligator mississippiensis (the same species as today's American alligator!), have been found.
• There were also other large crocodile-like reptiles like Thecachampsa sericodon.

Snakes and Lizards

Smaller reptiles also left their mark.

• Ancient boas (Boa constrictor) and other snakes are present.
• Lizards like Peltosaurus floridanus have also been identified.

Ancient Amphibians

Frogs and salamanders also lived in this ancient environment.

• Ancient frogs like Bufo praevius and Hyla goini have been found.
• A type of ancient salamander, Siren hesterna, also lived here.

Ancient Fish

The waters of ancient Florida were full of fish, including some very famous ones!

Sharks

• The most famous shark fossil found here is the tooth of the megalodon, a giant prehistoric shark!
• Other ancient sharks include ancestors of today's bull sharks (Carcharhinus leucas) and lemon sharks (Negaprion brevirostris).

Rays

• Ancient sawfish (Pristis sp.) were also present. These rays have a long, saw-like snout.

Other Fish

• Fossils of ancient gar fish (Lepisosteus sp.) have also been discovered.