the mind > mental capacity > memory > [adverb] > memorably
the mind > attention and judgement > importance > [adverb] > worthy of notice > memorably
1871 Carlyle in Mrs. Carlyle (1883) II. 242 Jean's look unforgettably sad and grand.
1899 J. W. Mackail I. 213 The powerful..face impressed itself unforgettably even on those who saw it but once.