Barrow Hills are spawned by Thaumcraft 3 in grasslands or relatively flat biomes. They always contain a dark node (can be VERY big, and spawn wisps) and are dug into the ground under a small hill much like a hobbit hole. These contain three chests with various rare loot, such as Knowledge Fragments or the rarer Oblivion Frame.
Structure and AppearanceEditBarrow Hills spawn in relatively flat biomes such as savannah, and appear as irregular hillocks betrayed by the stone entrance on the western side.
This entrance is blocked by two pieces of iron gate. Once inside, you find yourself in a ring-shaped upper level, featuring four columns with cobble steps as decoration, and a stairway in the northeast corner leading down to the main floor. (By this time, the mob spawners will be reacting to your presence, so a good strategy is to knock mobs into the central pit.)The main level features two mob spawners (from experience, one zombie and one skeleton) in the western corners, as well as the central pit. Cobble stairs smooth the 'lip' of the pit, and a ladder is incorporated into it. Three chests containing valuable loot (e.g. gold and thaumium ingots, steel or thaumium tools, enchantment books etc.) lie at the bottom of the pit.
The entire structure is mainly made of mossy and plain cobblestone, with the exception of the entrance which features iron grates and a carved stone block.
Barrows always contain a dark node, making it unpleasant if not impossible to use as a habitation. Exploration of barrows is thus best performed during daylight hours.
Although a dark node is usually high in Vis, it will perpetually spawn hostile wisps [for example, the Mortuus and Mallum variety]. It will generate high flux, so any sort of extended stay in the area could eventually lead to such phenomenon as Giant Angry Zombies nearby.