What is Santiago's dream in Coelho's The Alchemist?

The story opens
with Santiago at a dilapidated church where he stays for the night with his sheep. He dreams a
dream for the second time here and decides to go to a gypsy in town to have it read for him. It
is with the gypsy that Santiago describes the details of this dream. First, he is in the field
with his sheep when a child appears to him. The child then plays with the sheep, which causes
him to tell the child to stop. He believes that the sheep don't like strangers. Apparently, the
child ignores Santiago in the dream and continues to play with the sheep for a long time. All of
a sudden, the child gets up, takes him by both hands, and transports him all the way to the
Egyptian pyramids. This is curious to Santiago because in his inexperienced life, he had never
even known what the pyramids were; so, having a dream about something he had never seen or known
before proves that it is not of his own making. In the dream, the child then says to him,
"If you come here, you will find a hidden treasure" (13-14). The dream stops there and
Santiago wakes up. The gypsy then postpones payment for the reading and tells him to pay her ten
percent when he finds his treasure.