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In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between 56 and47.8 Ma, is preceded by the Thanetian Age and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the lower Eocene.
The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between 47.8 and41.2 Ma. The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene Subepoch.
The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals and were established using geographic place names where fossil materials were obtained.
The Arikareean North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 30,600,000 to 20,800,000 years BP, a period of 9.8 million years. It is usually considered to overlap the Oligocene and Miocene epochs. The Arikareean is preceded by the Whitneyan and followed by the Hemingfordian NALMA stages.
The Rancholabrean North American Land Mammal Age on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from less than 240,000 years to 11,000 years BP, a period of 0.229 million years. Named after the famed Rancho La Brea fossil site in Los Angeles, California, the Rancholabrean is characterized by the presence of the genus Bison in a Pleistocene context, often in association with other extinct Pleistocene forms such as Mammuthus. The age is usually considered to overlap the Middle Pleistocene and Late Pleistocene epochs. The Rancholabrean is preceded by the Irvingtonian NALMA stage, and it is succeeded by the Santarosean age.
The Hemphillian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 10,300,000 to 4,900,000 years BP. It is usually considered to overlap the Tortonian age of the Late Miocene and Zanclean age of the Early Pliocene. The Hemphillian is preceded by the Clarendonian and followed by the Blancan NALMA stages.
The Clarendonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 13,600,000 to 10,300,000 years BP, a period of 3.3 million years.
The Barstovian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 16,300,000 to 13,600,000 years BP, a period of 2.7 million years. It is usually considered to overlap the Langhian and Serravallian stages of the Middle Miocene. The Barstovian is preceded by the Hemingfordian and followed by the Clarendonian NALMA stages.
The Hemingfordian on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 20,600,000 to 16,300,000 years BP. It is usually considered to overlap the latest Aquitanian and Burdigalian of the Early Miocene. The Hemingfordian is preceded by the Arikareean and followed by the Barstovian NALMA stages.
The Chadronian age within the North American Land Mammal Ages chronology is the North American faunal stage typically set from 38,000,000 to 33,900,000 years BP, a period of 4.1 million years. It is usually considered to fall within the Eocene epoch. The Chadronian is preceded by the Duchesnean and followed by the Orellan NALMA stages.
The Duchesnean North American Stage on the geologic timescale is a North American Land Mammal Age (NALMA), with an age from 42 to 38 million years BP, representing 4 million years. It falls within the Eocene epoch. The Duchesnean is preceded by the Uintan and followed by the Chadronian NALMA.
The Uintan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 46,200,000 to 42,000,000 years BP lasting 4.2 million years. It falls within the Eocene epoch, preceded by the Bridgerian and followed by the Duchesnean NALMA stages.
The Wasatchian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 55,400,000 to 50,300,000 years BP lasting 5.1 million years.
The Clarkforkian North American Stage, on the geologic timescale, is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 56,800,000 to 55,400,000 years BP lasting 1.4 million years.
The Tiffanian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 60,200,000 to 56,800,000 years BP lasting 3.4 million years.
The Torrejonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 63,300,000 to 60,200,000 years BP lasting 3.1 million years.
The Puercan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), spanning the interval from 66,000,000 to 63,300,000 years BP lasting 2.7 million years.
The Harrisonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 24,800,000 to 20,600,000 years BP, a period of 4.2 million years. It is usually considered to overlap the Chattian and Aquitainian stages within the late Paleogene. The Harrisonian is preceded by the Monroecreekian and followed by the Hemingfordian NALMA stage.
The Geringian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 30,800,000 to 26,300,000 years BP, a period of 4.5 million years. It is usually considered to fall within the Oligocene epoch. The Geringian is preceded by the Whitneyan and followed by the Monroecreekian NALMA stages.
The Washakie Formation is a geologic formation in northern Colorado and southern Wyoming. It preserves many mammal, bird, reptile and other fossils dating back to the Lutetian stage of the Eocene within the Paleogene period. The sediments fall in the Bridgerian and Uintan stages of the NALMA classification.
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