The emphasis is on cladistics, taxonomy, and classification. If you are interested in dinosaurs' natural history or dinosaur extinctions, look elsewhere. Geologic Time A K-12 site that explains the age of the earth and the different geological time periods in clear, if somewhat cutesy language. Maps show the alignments of continents at different times, and there are useful definitions of such almost obvious concepts as large numbers. Since the Last Interglacial An atlas that describes in detail the vegetation and climates on various continents throughout the last 150,000 years.
Paleontologists use fossilized pollen grains and radio carbon dating to chart climate.
The maps are clear, and they cover nearly every continent. The language, however, is dry and scholarly. For the advanced and highly motivated. The Great Archosaur Lineage Archosaurs are a major group of animals known as diaspids. If that doesn't mean much, consider that they comprise the dinosaurs, pterosaurs, as well as present day crocodiles and the forerunners of contemporary birds.