Fossil Treasures of the Anza-Borrego Desert - The Last Seven Million YearsSouthern California's Anza Borrego Desert State park is a vast, mostly arid desert, but the ancient landscapes of Anza Borrego were richly populated riparian forests and savanna, and before that, there was a tropical inland sea teeming with marine life. The Park's eroded badlands provide North America's most continuous history of life for most of the last seven million years one of the richest fossil records of its time in the western hemisphere