Chief Brody costume from Jaws

[joberg]

Interesting...specially the pants

 

[Basin Bear]

Pants look like vintage slicker suit bottoms.

 

[67Beatle88]

The pants pockets are called frog mouths. You can try looking for western suit pants, they'll normally have them. A lot of mod suits also have them, however, it looks like he wears normal pockets in some scenes.