Here,
we run into our first apparent inconsistency. 
= yom has an unequivocal modern meaning of 'day'; and
= laylah or 'night'. The verse is concerned with what
the Shining Ones decided to call the explored and unexplored
parts of their chosen territory. In our interpretation, they
called the explored land - yom; and the unexplored land
ø laylah.
In other words, the parts on which they were enlightened became known as yom; and the parts on which they had no light became known as laylah. This discrimination took place ten thousand years ago, and the first interpretations of the written text were made between seven and eight thousand years later! We should not be surprised if, in the course of that lengthy period, yom and laylah became marginally changed in meaning.
So the 'light land' was yom and the 'dark land' was laylah - and after the exploration that had brought the words into being had been forgotten, it seems likely that 'land' was dropped from the expression - and yom in its simplified form, became 'light' or 'day'; and laylah became 'dark' or 'night'.
| jerusalem bible | (alternative genesis) |
|---|---|
| God called the light 'day', and the darkness he called nightT. Evening came and morning came: the first day. | The Shining Ones named the explored land yom, and the unexplored land they named layah. There was evening and there was morning - a first day [stage]. |
There has long been controversy over the division of the 'Creation Story' into parts of seven days - this has all the hallmarks of a redactor bent on tidying and labelling. And yet, it is perfectly logical for the Anannage to have conducted their establishment of Eden in stages; and that the opening stage should have consisted of the reconnaissance of the territory.
