University of California
Ucmp: The Cretaceous Period
This site from the UCMP Berkeley provides information about the Cretaceous Period, the last portion of the age of the dinosaurs and the continued break up of the continent of Pangaea.
Other
Black Hills Institute of Geological Research, Inc.: Ceratopsian
The Ceratopsian dinosaurs, described here, lived in the Cretaceous Period between 135 and 65 million years ago. This group included the Triceratops and the Torosaurus.
American Museum of Natural History
American Museum of Natural History: O Logy: Face to Fossil: Protoceratops
Questions and answers about Protoceratops andrewsi, presented as an "interview" with a museum's fossil. Learn about the dinosaur, the age of the fossil, and how the museum had it transported.
Museums Victoria
Melbourne Museum: Meet the Skeletons: Protoceratops Andrewsi
Protoceratops andrewsi was an herbivorous dinosaur from the Late Cretaceous Period, related to the Triceratops. Some information and pictures can be found here.