Kirtlington Quarry exposes limestones and clays of the Great Oolite Group that formed in the Middle Jurassic around 165 million years ago. The quarry, like many of the other quarries in the area, was used for the production of cement, and was worked for cement from 1907 to 1928.

The Jurassic rocks exposed in Kirtlington Quarry provide lots of evidence to tell us what the environment would have been like at the time these rocks formed. It is thought that Kirtlington lay near to the shore of a small barrier island, in a coastal environment, and would have been similar to the Florida Everglades today. These conditions attracted many animals to Kirtlington, and the quarry is famous among geologists for its rich diversity of fossils.

Dinosaur bones of a 15m long Cetiosaurus, and the tooth of a Megalosaurus have been found here, along with the teeth of flying reptiles called pterosaurs, and the remains of sharks, Long-Snouted Crocodiles, and a large marine reptile called a Plesiosaur. Kirtlington however, is most important for its mammal fossils, and the quarry is the richest mammal-bearing locality of Middle Jurassic age known anywhere in the world.