This is the Precambrian dimension. The biomes included are listed below. To open a portal click on it with the bone wand, which has been enchanted with the Enchantment of Time Reversal. The Enchantment of Time Reversal can be obtained from a Palaeobotanist villager, or as a rare chance on the crafting table. Note that the biomes in these dimensions are able to be extremely large, up to several thousand blocks across. Travelling 10 blocks in the overworld will move you 100 in a custom dimension though, and the main mod's config has an option to allow you to increase that if you felt the need. There are achievements for finding all biomes (biomes listed on the same line are regarded as equally valid for those achievements):
Hadean Era:
- Hadean Volcanic Wastes
- Hadean Magma Fields
- Hadean Smelts
- Hadean Crater Fields
Archean Era:
- Archean Tide Pools
- Archean Shallow Sea
- Archean Abyssal Chasm
- Archean Desolation
Paleoproterozoic Era:
- Paleoproterozoic Regolith
- Paleoproterozoic Shallows
Mesoproterozoic Era:
- Mesoproterozoic Carpet
Neoproterozoic Era:
- Neoproterozoic Microbial Plains
- Cryogenian Ice Desert
- Cryogenian Ice Ocean
- Tonian Sea
- Ediacaran Shallow Sea
- Ediacaran Extreme Hills
- Ediacaran Frondose Forest
- Ediacaran Deep Trench
- Ediacaran Stromatolite Pavement
- Ediacaran Shallow Reef
- Ediacaran Sparse Sea
General biomes:
- Proterozoic Barren Hills
- Proterozoic Rift
- Caustic Quagmire