Genesis and Internal Contradictions

I've so many times heard people claim that the Bible was internally inconsistent, but I always seemed able to logically dispatch their claims without batting an eyelash. It was the ones I found for myself that I found so much harder. I don't think my faith can be reclaimed until I hear a really convincing answer to the following apparent contradiction:

1. Heaven is a firmament between waters:

Thus God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament; and it was so. 8 And God called the firmament Heaven. So the evening and the morning were the second day (Gen 1:7-8)

2. The sun moon and stars are put in this firmament:

14 Then God said, Let there be lights in the firmament of the heavens to divide the day from the night; and let them be for signs and seasons, and for days and years (Gen 1:14)

3. Birds fly in thisfirmament: Then God said, Let the waters abound with an abundance of living creatures, and let birds fly above the earth across the face of the firmament of the heavens (Gen1:20)

Now, it seems patently obvious to me that the sun and the moon are not between a pair of waters. And even more obvious that birds and the sun do not share the same firmament between waters. It seems to me that these verses reflect a very primitive cosmology where the sun was thought to be in the sky, rather than in outer space.

If you have an answer for this. I beg you to share it.