The secret place...

My frame was not hidden from you,
when I was being made in secret,
intricately woven in the depths of the earth.

Psalm 139 v 15

This verse from one of David's most famous Psalms is another example of how the idea of being created from the dust can be a metaphor for the natural process. The 'earth' described here is the same word used in the opening chapter of Genesis where we read that 'God called the dry land Earth'.

So is David saying that he came into being in some mysterious location near earth's molten core? Of course not:

For you formed my inward parts;
you knitted me together in my mother's womb.
V 13

It's a picture, and part of the wider view that describes our mortal, material existence. This is relevant to one of the scenarios by which we can understand Adam and Eve (discussed here).