Adventure Comics #306~312
(the debut of the Legion of Substitute Heroes, Element Lad, Lightning Lass, the return of Lightning Lad)
Jimmy Olsen #72 (Jimmy is made an Honorary Legionnaire)
Adventure Comics #313~317 (the debut of Dream Girl)
Legion Profile Pages from Superman Annual #4 and Adventure Comics #316
We pick up in year three as Saturn Girl is still the leader. Five rejected Legion applicants form the Legion of Substitute Heroes, and eventually meet up with the true Legion. Stone Boy wins a contest to gain membership, but turns it down to stay with the Subs. Lightning Lass joins to take her dead brother's place, but stays even after he is revived. Dream Girl joins just long enough to change Ayla to Light Lass. Oh, and the entire Legion is killed by Mr. Mxyzptlk.