public void registerBiomes() {
super.registerBiomes();
register(VanillaBiomes.NETHERRACK);
final BedrockBoundPopulator bedrock = new BedrockBoundPopulator();
bedrock.addBound(0, 1, BEDROCK_DEPTH);
final BedrockBound top = new BedrockBound(HEIGHT - BEDROCK_DEPTH, 1, BEDROCK_DEPTH);
top.setFlipped(true);
bedrock.addBound(top);
addGeneratorPopulators(
bedrock,
new NetherCavePopulator(),
new BlockPatchPopulator(VanillaMaterials.SOUL_SAND), new BlockPatchPopulator(VanillaMaterials.GRAVEL));