A crack in the doorway

I pushed past the hem of the floor curtain, heading straight toward the bright line of daylight at the balcony door! Suddenly—whoosh! A cool breeze ruffled my hair. I froze solid right on the aluminum track, holding my breath... One second... two seconds. Nothing leaped out! I leaned around the sliding door frame and peered into the sunny breeze. Right outside on the tiles sat a fallen terracotta flowerpot with tiny grey pebbles scattered around it. The outside world is right there through the glass... could real fossils be hidden out under those stones?