The main story is actually very good and well-written; I have read it with utter pleasure.
However, the author is really convinced that the story of the bible (no capital letter, sorry!) must be taken literally, including the fact that the world is only a couple of 1000 years old and the flood actually happened. The inclusion of the side trips - that do not contribute to the main story - to this early world where the lion and the sheep live peacefully next to each other (and the dinosaurs!) left me totally baffled! How can a man write a decent SF story and mix this with such archaic beliefs?
But, if you can disregard these strangely out-of-place parts, there is still a decent SF story to discover.