In geology, the period that followed the Cretaceous is known as the Paleogene period. The Cretaceous period, which spanned from approximately 145 to 66 million years ago, was the last period of the Mesozoic Era, also known as the Age of Dinosaurs.

The Paleogene period, which followed the Cretaceous period, lasted from around 66 to 23 million years ago. It is part of the Cenozoic Era, also known as the Age of Mammals. The Paleogene period is further divided into three epochs: the Paleocene, Eocene, and Oligocene epochs.

During the Paleogene period, significant geological and biological changes occurred on Earth. The extinction event that marked the end of the Cretaceous period resulted in the demise of dinosaurs and many other species. This extinction event also paved the way for the rise of mammals, which diversified and flourished during the Paleogene period.

The Paleocene epoch, which began immediately after the Cretaceous period, was characterized by a warm climate and the recovery of ecosystems after the mass extinction. Mammals rapidly diversified during this time, taking advantage of the ecological niches left vacant by the dinosaurs. The early primates, ancestors of modern-day monkeys, apes, and humans, also appeared during the Paleocene epoch.

The Eocene epoch, which followed the Paleocene, was marked by a greenhouse climate with elevated global temperatures. This epoch witnessed further diversification and evolution of mammals, including the emergence of early whales and large land mammals like the brontotheres and early horses. The Eocene epoch also saw the spread of modern plant groups, such as grasses and flowering plants.

The Oligocene epoch, the last epoch of the Paleogene period, was characterized by a gradual cooling of the climate and the expansion of grasslands. Mammals continued to evolve and diversify during this time, with notable appearances of early hominoids, the family that includes humans and their closest relatives.

In conclusion, the Paleogene period followed the Cretaceous period in geology. It was a time of significant changes in the Earth's climate and ecosystems, marked by the rise and diversification of mammals, including our own primate ancestors. Understanding the geological history of our planet helps us comprehend the evolution and development of life on Earth.

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