In 1980, I read a book whose story details I recall only dimly. I do not recall the title.
Two children travel far from home to another place. I forget the purpose or motive for their journey. I believe it may have been a brother and a sister.
At one point during their long journey, they sleep in a friend / ally / friendly stranger’s houseboat (or boat or water-home of some kind.) The young girl (I think) listens to the water lapping up under the floor as she is going to sleep.
Near the end of the book, they encounter a civilization which had at some point stopped living in the world and now existed in a spirit form. The memory I recall when reading about this encounter, is that an individual (s) of this culture were rowing by them, or above them, as if rowing through the air, as spirits, in a “spirit canoe.”
The mood of their encounter with this race of spirit people was haunting, nostalgic, and a sense of loss or grief for the children. As a ten year old, I was moved somewhat sorrowfully when the children learned of or interacted with these spirits.