This material describes an older, pre-Wiccan layer of essentially the same four-direction cosmological structure already laid out in the elemental correspondence tables above — and understanding it requires holding three distinct "layers," working outward from the center of the ritual space to its farthest conceptual boundary.
The innermost layer is the Elements themselves — Air, Fire, Water, Earth as already discussed, called directly into the circle in ordinary practice.
The second, farther-out layer is the Watchtowers: four directional gates or portals, imagined not at the boundary of the physical circle but at the far boundary beyond it, one per cardinal direction. These are described as serving a dual function — simultaneously protective (a boundary/ward function) and as passage-points (an opening/threshold function) — which is a slightly paradoxical-sounding combination until you consider that a well-guarded gate is, definitionally, both things at once: it keeps unwanted things out precisely by controlling what's allowed to pass through.
The outermost, third layer is the Watchers: spiritual beings understood to preside over each individual Watchtower. The source material traces this concept specifically to Judeo-Christian esoteric tradition, citing Genesis 6 (the "sons of God" who intermarry with human women, commonly read in later esoteric and apocryphal tradition as a reference to fallen angels) and the Greek term Grigori ("watchers," the term used for this same class of being in the Book of Enoch and related apocryphal literature). Importantly, the Watchers are framed as neither inherently good nor evil — simply vast and ancient, a genuinely different ethical register from either the "harmless" elementals above or the more morally loaded "demons."
Practically, the source material notes that some traditions — specifically citing Gardnerian practice — call the Watchtowers before calling the elements in a working, reflecting the "outermost first, working inward" logic implied by the three-layer structure above. But most modern eclectic practice omits the Watchtower/Watcher layer entirely, working with the elements alone, for simplicity — which is consistent with the broader pattern, documented throughout this outline, of more traditional, ceremonially-elaborate lineages retaining older, more baroque ritual layers that eclectic and solitary practitioners have widely streamlined or dropped.