As you stated in "What does the Bible say about Evolution, Cavemen, and Dinosaurs" God created as mentioned in Genesis 1. Could evolution still have occurred? What was the length of days in those days??
Answer
It has long been argued by those who would like to accept both the Genesis account of creation and one of the theories of evolution that it is possible the days were longer in Genesis 1. There is nothing that definitely denies the "long day" theories. It is possible.
I find it unlikely, though, based on a scripture and a scientific argument. First the argument from science. If the days (and supposedly the nights) of Genesis 1 were equal to what would now be considered many years then the growth of anything would be questionable. The general assumption would be that the days and nights were of approximately equal length, as they now are. If this were so then most plants, at least, would have died out before they could seriously evolve. Even animals would have a difficult time. Life as we know it is based on a cycle of light and dark. If the dark were equivalent to hundreds of our years most plants would die out in the night, and most animals would go crazy. If the day were as long as several hundreds of years then most animals and many plants would not survive, as shown by recent experiments on the effects of not having these cycles of light/dark. Think of it as jet lag on a grand scale.
The argument from scripture is based on Exodus 20:9-11. "Six days shalt thou labour, and do all thy work: But the seventh day is the sabbath of the LORD thy God: in it thou shalt not do any work, thou, nor thy son, nor thy daughter, thy manservant, nor thy maidservant, nor thy cattle, nor thy stranger that is within thy gates: For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it." If the Lord created the earth and everything in it in six super-long days why would he specify one twenty-four hour day as the Sabbath of the Jews? Since the Sabbath was compared to the days of creation, and since the Sabbath is one twenty-four hour day, it is likely that the days of creation were of the same duration as current days.
In the final analysis, though, the scriptures do not definitively say the days of creation were the same length as days are now. However, there is little difference in stretching the days to cover long eras and simply calling Genesis 1 a myth.