|This article is about an older version of DF.|
If you're looking for information on Caverns in the current version of the game, please click here.
This article is a rough guide to what you can expect to find as you dig into the mountain. Every mountain in Dwarf Mode has the same internal geological features stretching from the top edge of the map to the bottom in a narrow band, found in the same sequence. From west to east, they are: the underground river, the chasm, the magma flow, the glowing pits, and adamantine. The first three features (river, chasm, and magma) zigzag back and forth quite a bit, so the gems and ores listed may occasionally be found slightly on the near side of the corresponding feature. For instance, you may find a vein of hematite extending just a little bit west of the chasm.
Additionally, when mining gems, you will occasionally get a message that "a miner has found some <gem> mixed in with <some other gem>". This can happen anywhere in the cave and will always produce a gem (of the same color) one level rarer than the type displayed in the cluster. For instance, rose quartz (red) may have red spinel mixed in with it, red spinel may have ruby, or ruby may have red diamond. As always, the Random Number Generator is both your enemy and your friend.
Usually one kind of enemy humanoid will be predominant at each geological feature. For instance, if you encounter antmen at the chasm, you will not see many, if any, ratmen or batmen. However, you may still encounter any of the nonhumanoid enemies.
 Initial rock
The "initial rock" is the part of the mountain that stretches from the mountain face to the cave river.
- Sphalerite (zinc ore; half of brass)
- Cassiterite (tin ore; half of bronze)
- Malachite (copper ore; other half of both bronze and brass)
- Galena (silver ore)
 Cave river
The cave river is between 5 and 8 spaces wide, and twists and turns between roughly 48 spaces from the cliff face to about 103 spaces from the cliff face. It is surrounded by limestone 1-2 squares deep on both banks. "Offshoots" of the river will contain either waterfalls or small chasms. These offshoots will stay inside the range of the river, that is, offshoots would appear on the left side only when the river bends far to the right.
 Waterfalls and sinks
Waterfalls appear at the ends of "offshoots" that flow downstream into river (i.e. offshoots that point north). In their center, they produce a "fine mist" which causes a happy thought for each dwarf that comes into contact with it.
Sinks appear at the ends of "offshoots" that receive a downstream flow of water from a river (i.e. offshoots that point south). They are surrounded by a few chasm tiles. A dwarf that falls in the water at the end of one of these channels will immediately die, with the message "fell into a deep chasm."
Directly interacting with the river (drinking, fishing, etc.) will trigger subsequent attacks from its denizens. Using wells built anywhere inside the mountain can also trigger attacks, which will sometimes cause enemies to emerge from the wells themselves.
 After the river
The chasm is between 3 and 5 spaces wide, and angles between 148 to 200 spaces from the cliff face. The chasm tends to make sharper turns than the river, and its offshoots are always straight and between 1 and 2 spaces wide.
- Giant bats
- Giant rats
- Large rats
- Naked mole dogs
- Giant moles
- Giant cave spiders
- Iron men
Chasming refuse will trigger attacks from chasm-based creatures. This can result in an extended series of attacks as creatures emerge, kill or get killed, and leave remains behind which get thrown into the chasm, triggering more attacks. Flooding the chasm with magma will increase attacks for a short time, then attacks will stop as the bottom of the chasm fills with magma (the center of the chasm turns red). Flooding the chasm with water may reduce attacks, but will never eliminate them.
Attacks from trolls are very rare, but can be dangerous. Trolls are strong and are capable of destroying buildings (including doors and floodgates). Gremlins can throw levers, which can lead to all sorts of havoc, so hide your levers behind a door and a trap or two. But be warned, Gremlins themselves do not set off traps.
 After the chasm
Rare gems (only found when mixed in with the above gems):
- Native gold
- Native platinum
- Hematite (iron ore)
- Bituminous coal (technically not an ore but with many related properties)
 Magma flow
The magma flow is between roughly 240 and 310 spaces from the cliff face, and is between 7 and 11 spaces wide. Only steel or adamantine may be used to create any bridges or aqueducts that cross it, though there is an exploit where only the topmost material selected to build a structure determines its material. The magma river is surrounded by obsidian 1-2 squares deep on both banks.
 The Pits
Digging past the magma is extremely dangerous. From about 330 to 360 spaces from the cliff face, small eerie glowing pits are randomly scattered. These pits are usually arranged such that it is impossible to completely avoid them when trying to dig past them (unless you're psychic). Demons emerge from pits not long after they are unearthed, so keep your military ready.
Approximately a half-dozen demons will show up shortly after you first reach the pits, and not all at once. They are tougher than anything else you are likely to have encountered before this point, and can easily wipe out an entire fortress that is not thoroughly prepared for their arrival. They are wholly immune to traps, magma and steam. Frog demons can breathe underwater, but the others can't.
Beyond the pits is one of the game's greatest rewards: adamantine.
The final part of the cave is a layer of raw adamantine in front of a chasm that you cannot go past (because the game simply won't scroll that far). The chasm occasionally sends a 1x10 cut to the left that is surrounded by adamantine. The adamantine is 1-2 squares thick on the edge of this chasm, much like limestone lines the edge of the cave river. Once you start mining raw adamantine, the game will check each season and use your total raw adamantine mined so far as a percentage chance to doom your fortress. When this happens, a one-season timer will start, and then the game will end with a screen describing how you have dug too deep, and released a demon. There is no safe level of raw adamantine to mine: Once you have mined any, your game will end eventually. You can find (and kill, if you're fast, lucky, and smart) this demon in adventurer mode if you find your old fortress again.