They dove underwater to the soft river bed, Onto darkish green plants with a smidgen of red.
1845, perhaps from Scottish smitch "very small amount; small insignificant person" (1822). Cf. Northumbrian dialectal smiddum "small particle of lead ore" (1821).
To look for something as if by smelling: I figure I can't do any worse than the others by coming out here in the street and trying to smell it out (1538+)