Drew I don't believe the first one is terribly old , the swiveled toothed jaw would indicate that its some type of cinch or adjustment buckle (a type of suspender , vest or even trousers ) my guess would be late 19th century . Your other buckle looks much older and close to the types around the revolutionary war era a type of buckle , I can't give you a definitive answer if its civilian or military as both used it. you remember which site it came from ? you might find more evidence of the type of area it was .
Dan