Matthew Crawford has kindly pointed out a passage by Cyril of Alexandria discussing chapter divisions. This passage is new to me. It may be found in his commentary on the Old Testament, in the preface to the Glaphyra in Genesim. This is online in PG 69, col. 16. I don’t know a lot of Greek, and find Migne’s Greek difficult to use. But the Latin translation he supplies says:
Sciendum vero etiam hoc, quod cum De adoratione et cultu in spiritu et veritate XVII libros scripserimus, multamque in illis contemplationem copiam complexi simus, capita huic operi inserta certo consilio praetermisimus, et inexaminata reliquimus: tamenetsi interdum accidit ut alicuius eorum necessaria de causa meminerimus.
My not very good stab at translating it (but better than nothing) is:
But also know this, that since we wrote 17 books On adoration and worship in spirit and in truth, and we included a great quantity of thinking in them, we deliberately omitted chapters inserted in this work, and left them unexamined: although sometimes it happens that we may refer to some of them out of necessity.
UPDATE: Matt wrote to me with his translation of these words, and I had misunderstood them as referring to chapter titles rather than chapters. The point is that both the Glaphyra and the De adoratione are Old Testament commentaries, and Cyril was omitting discussion of those chapters he had already discussed. The De adoratione is in PG68, complete with chapter divisions. He writes:
The chapter divisions Cyril is referring to are in his OT commentary called De Adoratione. However, in the preface to his other OT commentary called Glaphyra, he makes reference to the chapter divisions in De Adoratione. If you look at PG 68 you can see the chapter divisions there with their titles.
Also, I translated the passage from the preface to Glaphyra a bit different than you did, though I could be mistaken! Cyril’s Greek is tough and I often find myself struggling. If it wasn’t for the Latin translation in PG, I would be completely lost on a number of passages. Nonetheless, here’s what I got:
‘And one should see that since we have composed 17 books in De adoratione et cultu in spiritu et veritate and gathered together much fullness of thoughts in them, we have intentionally passed over those chapters in the present writing, and we have kept what is unexamined.’
So as I read it, Cyril is saying that he is not including in the Glaphyra those topics he covered in the De Adoratione. But as I said, I could be mistaken. Please let me know what you think.