To focus on Jeffers's women seems beside the whole point of Jeffers's philosophy, which is that men and women alike ("You and I, Cassandra") are doomed in their human, evolutionarily misguided drive to wreak destruction through greed, avarice, desire, and power-mongering. No doubt there is a personal psyche at work in Jeffers which allows him to portray women as so much bigger, more flexible, stronger than most of his male figures. But I interpret Jeffers as caught in the paradox of trying to have an "inhuman" vision while still bound by his humanity, which includes the fact that he is a man and limited by that gender.
It is not accidental that, in this lyric poem, "Cassandra," coming after the bitter time of his Double Axe persecution and unofficial literary blacklisting, he makes himself equal or a twin to a woman. It is a gesture, I think, showing his stance as a poet, and one that can be found in many other of the short lyric poems. The poet is outside, an observer. "It" (the poet) can be either male, as Jeffers is, or female, as Cassandra is. The haunting lament, "You and I, Cassandra," is a statement of his equality with her, and the hopelessness of the human condition out of which, for the duration of the poem, they both remain. They both have given up their personal (i.e., gender) identities in the pursuit of truth. This lyric offers a glimpse into Jeffers's view of the godly androgyny which he wishes he could imagine in an "inhuman" world. When Mark Mitchell illustrates that Jeffers refers to God with the masculine pronoun yet implies a female identity, what I draw from that is androgyny--that god is neither male nor female, or both, in some non-sexual, non-gendered way. I think we must accept that Jeffers could himself hardly conceive of what this meant.