Meanings of strangely solid in English

But as the weeks passed Brother retained his strangely solid appearance.

In a moment, the images were completely wiped out, and the region within the coils was filled with a strangely solid blackness.

Most doorways were without doors and the blackness they framed seemed strangely solid; even in surrender something remained that was impenetrable, mystifying.

Nearer the tug was another bank of mist, that looked strangely solid but ragged, as if it were wrapped about something with a broken outline.