Was the Tomb open or closed when the women arrived?

The editors of The Skeptic’s Annotated Bible see a contradiction in the following accounts (dutifully quoting from the KJV):

The Tomb was Closed:

• “The angel of the Lord descended from heaven, and came and rolled back the stone from the door, and sat upon it.” (Matthew 28:2)

The Tomb was Open:

• “And they found the stone rolled away from the sepulchre.” (Luke 24:2)
• “Who shall roll us away the stone from the door of the sepulchre? And when they looked, they saw that the stone was rolled away.” (Mark 16:3-4)
• “The first day of the week cometh Mary Magdalene early, when it was yet dark, unto the sepulchre, and seeth the stone taken away from the sepulchre.” (John 20:1)

Part of the difficulty lies in the fact that The Skeptic’s Annotated Bible does not truthfully present or examine all the evidence. First, the quote of Matthew 28 is incomplete. Starting from verse 1 we read in the NASB (a clearer translation of the Greek), “Now after the Sabbath, as it began to dawn toward the first day of the week, Mary Magdalene and the other Mary came to look at the grave. And behold, a severe earthquake had occurred, for an angel of the Lord descended from heaven and came and rolled away the stone and sat upon it.”

Mark 16 lets us in on a conversation the women were having on the way to the tomb—clearly the women were expecting to find it closed because they were talking. Mark 16:2-4 tell us plainly, “Very early on the first day of the week, they came to the tomb when the sun had risen. They were saying to one another, ‘Who will roll away the stone for us from the entrance of the tomb?’ Looking up, they saw that the stone had been rolled away, although it was extremely large.” They found the unexpected—it was already open, just as Luke and John record! Matthew tells us how it was opened.