। ॥ ३२८ ॥
In plain words
There is ignorance, and there is the reflected awareness that ignorance has fenced in — and both of them rest on something. That support, consciousness pure and unmixed, is what is called turya, the Fourth.
Close to the Sanskrit
Of both — of nescience and of the reflection delimited by that — the support, the pure consciousness which is: that is declared to be the Fourth.