- Paleozoic Era
The time of "ancient life", before backpacking, from about 542 to 250 million years ago. It saw the development of all classes of invertebrates except for insects, the appearance of seed-bearing plants, and of amphibians and reptiles. Basically from the age of trilobites to that of reptiles.
The Paleozoic Era was before my time, but I found some good fossils from there. And my uncle Bob kinda remembers it too.