Sullivan appears to have made a substantial body of notes on his contribution to the work, which he co-edited with Eugene O'Curry, titled 'The Manners and Customs of the Ancient Irish' (see link). This large, bound notebook also has notes in the rear, which have been titled 'Prof O'Curry's lectures on the m[anu]s[cript] materials of ancient Irish history'. Further investigation of the contents of the notes would be required to understand whether these notes were made in preparation of the publication of their work, or are notes on their published work.