This is the Precambrian dimension. The portal block needed to get here and 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):
Precambrian: Portal block: Stromatolite - hint you need something sticky to hold falling blocks in place
Hadean Era:
- Hadean Volcanic Wastes
- Hadean Magma Fields
- Hadean Smelts
- Hadean Crater Fields
Archean Era:
- Archean Tide Pools
- Archean Shallow Sea
- Archean Abyssal Chasm
Paleoproterozoic Era:
- Paleoproterozoic Regolith
- Paleoproterozoic Shallows
Mesoproterozoic Era:
- Mesoproterozoic Carpet
Neoproterozoic Era:
- Neoproterozoic Microbial Plains
- Cryogenian Ice Desert
- Cryogenian Ice Ocean
- Ediacaran Shallow Sea
- Ediacaran Extreme Hills
- Ediacaran Frondose Forest
- Ediacaran Deep Trench
General biomes:
- Proterozoic Barren Hills
- Caustic Quagmire
Project members
Aecht_Rob
Owner