Also, the ocean is identified with mind in Śatapatha Śruti & the Trayī is said to be dug out of the mind-ocean by the Devas. Goes with Taittirīya Āraṇyaka’s cidasi samudrayoniH.
Now, since later day Sampradāyas understand Cit to be the beginningless, sentient entity known as the Ātmā, one may surmise that such vākyas indicating some sort of causal relationship between the insentient manas & sentient cit are perhaps partial insights.