Undated letters which could not be placed in order on internal evidence have, so far as was possible, been left in the positions in which they came to the Library. Lists of F. Mendelssohn Bartholdy's letters are in MS. M. Deneke Mendelssohn d. 18, fols. i-iii.

Here are included 40 letters or parts of letters from F. Mendelssohn Bartholdy, including:

(fols. 1-4) Drafts of F. Mendelssohn Bartholdy's two letters, 13 and 20 Aug 1836.

(fols. 16a-b and 147-148) Two letters from Lea to Mme. Jeanrenaud.

(fols. 78-79) Letter from Cécile to her sister Julie, 22 Dec 1837.

(fols. 183-184) Copies by Rebecka Dirichlet of parts of F. Mendelssohn Bartholdy's letters to herself, 24 Jul 1836, and to their mother, Lea Mendelssohn Bartholdy, 9 Aug and 9 Sep 1836 (the first two extracts were printed in Die Familie Mendelssohn).