Either use the crossbow and rope to cross the cemetery, or drop into the red fire barrier by hanging over the cemetery and prying off the lid of the grave to get the jewel. There will be a clock puzzle in the room. There is a clock to the left behind the wall paper. Press the buttons in the following order: 3 o'clock, 12 o'clock, 6 o'clock, 5 o'clock. You can now get the Golden Cross.