A stab at discerning a pattern in the Genesis toledoth sections:

Creation, 1:1-2:3

1. Generations of heaven and earth, 2:4-4:26 (beginnings, along with fall in Eden and Cain’s fratricide)

2. Generations of Adam, 5:1-6:8 (genealogy with ages)

3. Generations of Noah, 6:9-9:29 (lengthy narrative)

(New Creation, 8:1-9:29; see below)

1’. Generations of Shem, Ham, Japheth, 10:1-11:9 (new beginnings, ending with fall of nations at Babel)

2’. Generations of Shem, 11:10-26 (genealogy with ages)

3. Generations of Terah, 11:27-25:11 (lengthy narrative)

1”. Generations of Ishmael, 25:12-18 (list of descendants without ages, like table of nations)

3”. Generations of Isaac, 25:19-35:29 (lengthy narrative)

1”’. Generations of Esau, 36:1-37:1 (list of descendants without ages, like table of nations)

3”’. Generations of Jacob, 37:1-50:26 (lengthy narrative)

The last four sections are iffy, and might be better identified in a 4-5-4’-5’ pattern.  In terms of “genre” at least, these toledoth match the 1 and 3 sections of the second cycle.

The opening double cycle is divided by the flood narrative, and embedded within the Noah toledoth is a new creation story that roughly corresponds to the seven-day sequence of Genesis 1:

Day 1: Wind (Heb. ru’ach ), 8:1; cf. 1:2

Day 2: Water sources above and below close, 8:2; cf. 1:6-8

Day 3: Waters separated, dry land appears, 8:3-5 (plants, 8:11); cf. 1:9-13

Day 4: Window of ark, 8:6 – link to heavenly bodies?; cf. 1:14-19

Day 5: Birds sent out, 8:7-12; cf. 1:20-23

Day 6: Animals pour out on the earth, Noah as new Adam; 8:13-9:17; cf. 1:24-31

Day 7: Noah’s vineyard, rest, and Ham’s fall, 9:18-29; cf. 2:1-3 (or, 2:1-3:24)