What can be "in" a mountain?
I come from a language that heavily uses in as a preposition, so I often overuse it in English. I am trying to differentiate between things that can be in a mountain vs. things that can only be on a mountain. Also, is there a difference between in and inside, because every time I make a mistake like that, people correct me and explain that what I've said basically means inside the mountain.
So, for example, can I say that a peak is in a mountain rather than on a mountain? And generally, can something be in a mountain without being inside it?
Things which can be in a mountain are principally those which intrude inwardly upon its profile or its expected profile, or are entirely encompassed by its expected profile. For example, there can be a hole, or a ravine, or door in a mountain, -- as there can be a hole in an apple, -- because they are inward projections or modifications when compared to the expected profile of the mountain. "The door in the mountain leads to a magical kingdom".
There can be gold, or other minerals, in a mountain, -- as there can be a worm in an apple, -- as they are encompassed by its profile. But these are also inside the mountain (or apple), which includes only those things which are in a mountain and which are also not evident from its surface. In these contexts inside is more likely to be used, but in is also correct. "There is a dragon inside the mountain".
More generally, surface features of any kind are on the mountain (including those things which are in the mountain but not inside it, such as ravines). This includes boulders, ravines, and tea shops. "There is a tea shop on Mount Snowdon".
Something as fundamental to a mountain as a peak, however is of the mountain, as it is a fundamental constituent part. In contexts where, for example, a dragon is known -- distinctively and crucially -- to sleep inside Mount Fire, it can be referred to as the dragon of Mount Fire as it is an important constituent of that mountain. "The north face of the Eiger is hellish".
Prepositions are slippery and complex in all language. Good luck.
There are many, many things that can be in a mountain. The Corpus of Contemporary American English and the British National Corpus list some of them:
- cracks
- a link
- no progress
- us
- Alexander VII
- about 1,100 people
- other military forces besides NORAD and Northcom
- 60,000 slave laborers, one of them Rudy Kennedy
- a door
- a hole
- a cave
- a warm way station
- a stone house
- a school
- Helm's Deep
- another hole
- one of these cloaking shields
But no, what clearly cannot be in the mountain is its peak.
The other answers have addressed "in a mountain" competently, but when skimming I noticed no one presented the similar (and common) case of "in the mountains," which only means being among them, without regard to being above or below the surface of the terrain.