For 10 points, name this object which subtitles National Treasure II.
One character pretends to drop her earring to give another time to find the seal of this object, and the code XY 234786 is needed to access it. The protagonist finds this code after going to Mount Vernon and kidnapping the president, the only person who has access to this object. It is the last link to the lost city of Cibola, and Ben Gates finds it at the Library of Congress after being told to look at its page 47. For 10 points, name this object which subtitles National Treasure II. 
One character pretends to drop her earring to give another time to find the seal of this object, and the code XY 234786 is needed to access it.
The {Book} of {Secrets}