Europe is relatively rich in fossils from the Jurassic-Cretaceous boundary, and much of what is known about European dinosaurs dates from this time. As the timeline below illustrates, there are substantial gaps in our knowledge from the rest of the Mesozoic. The absence of dinosaur genera from this time is because few fossils have been discovered, and almost certainly not because Europe contained few types of dinosaur—except, perhaps, immediately after the Triassic–Jurassic extinction event.