Most of the draft usage of the composition of I.1 from VI.B. 15 is concentrated in the first-draft stage through the fair copy stage (1*2/2*2). The latest use of any entry for I.1 is "ordurd" (VI.B. 15: 224; back cover recto) which was not added until the revision of the transition 1 pages (1.5/2.5) in early 1936 (JJA 44: 250; BM MS 47475-12v; FW: 023.04).
The Museyroom and Pranquean episodes have the greatest concentration of notes in VI.B. 15 but there are other important notes concerning I.1 including a draft of the opening 100 letter thunder word (VI.B. 15: 155); the thunder word for the Pranquean episode along with a list of thunder words from various languages (VI.B. 15: 169); the frog words (VI.B. 15: 164); about one quarter of the first draft of the Finn passage (2*2‡) appears on two pages (VI.B. 15.176-7); the infamous "Howth Castle & Environs" (VI.B. 15: 33); and the original closing sentence for the chapter "High Cost Everything" (VI.B. 15: 84) (this was changed to "hubbub caused in Edenborough" in the redrafted pages of the fair copy (1*2+/2*2+) (JJA 44: 137; BM MS 47472-40).
VI.B. 12 contains extensive material for I.1, but only as random notes scattered throughout. A small majority relates to the Pranquean episode (VI.B. 12: 128; 130; 140); there is a reference in anticipation of the "100 lettered name." (VI.B. 12: 140) The density of references to Belgium towards the end of this notebook (VI.B. 12: 163-5; 181; 184) suggest that it preceded VI.B. 15. This agrees with David Hayman's and Danis Rose datings of this notebook at mid 1926 (JJA 31: xvii; Rose 1995, 28). Rose states--without elaboration--that there is a missing notebook in-between VI.B. 12 and 15. I am grateful to Geert Lernout for his transcription and annotations to VI.B. 12.