init.lua

	minetest.register_on_generated(function(minp, maxp)
		if minp.y < 0 and maxp.y > 0 then
			for x = minp.x, maxp.x do
			for z = minp.z, maxp.z do
				minetest.env:add_node({x = x, y = -1, z = z}, {name="my_mod:bedrock"})
				minetest.env:add_node({x = x, y = 0, z = z}, {name="default:dirt_with_grass"})
			end
			end
		end
	end)