Formal names should be written in full in running text, but may be abbreviated where space is limited (eg tables, maps):
Mount Wellington not Mt Wellington
Abbreviations for topographical features do not take stops:
B bay
C cape
Cr creek
G gulf
I, Is island, islands
L lake
Lgn lagoon
In inlet
Mt mount or mountain
Mts mountains
Pk peak
Pen peninsula
Pt point
R river
Ra range
Str strait