Word for naturally occurring land formations, that starts with S?

Factual Questions
21

3 points!

22

Spit
Saltation
Solution
Sequence
Superposition
Suspension

23

I have a hunch the OP’s dad is thinking of “spur” (synonym of “salient”). It’s sort of a convex form of a re-entrant.

24

Scree?

25

supervolcano