The Lost Cities: A Drift House Voyage

From the jacket:

Returning for the summer to Drift House, their uncle’s seagoing mansion, Susan and Charles Oakenfeld find themselves separated when a tidal wave sweeps the house away. Charles is stuck up a tree with a parrot and a mysterious book, while Susan and Uncle Farley are adrift on the Sea of Time. As each attempts to track the source of the time squall that set the tidal wave in motion, it soon becomes clear that they are separated not just by space but by centuries.

From the coast of Newfoundland to the rocky shores of medieval Greenland to the tumbling Tower of Babel, Charles and Susan are in for much more of an adventure than they could have imagined, and whether or not they get home again depends upon their brother, Murray, and his mysterious alter ego, Mario...