The documents are not FROM the time in question, or close enough to be authoritative, such as the Book of Genesis of course.
And, Faith, in your timeline, just how long was it between Cain killing Abel and Moses writing the report down? A few months? A couple of decades? "Close enough to be authoritative," sure - but how long is that?
"The Christian church, in its attitude toward science, shows the mind of a more or less enlightened man of the Thirteenth Century. It no longer believes that the earth is flat, but it is still convinced that prayer can cure after medicine fails." H L Mencken