Sentence:  Ona was blue-eyed and fair, while Jurgis had great black eyes with beetling brows, and thick black hair that curled in waves about his ears—in short, they were one of those <WSD>incongruous</WSD> and impossible married couples with which Mother Nature so often wills to confound all prophets. 
Meaning of the word marked with <WSD> tags:  Not similar or congruent; not matching or fitting in.