The Girl with the Jade Green Eyes by John Boyd 1979 UK Penguin Vintage
When the encounter long sought by mankind -- first contact with intelligent beings from outer space -- occurred two years ago in a remote area of the Idaho Panhandle, the event was not marked in the heavens with strange lights or on Earth with newspaper headlines. It began prosaically one Thursday morning in late May...
"Where are you from?"
She glanced toward the eastern ridge, studying it, and for a moment he thought she might point to a rock or a tree. Weighing her answer carefully, she pointed toward the top of the ridge and said, "From there."
"From the other side of the mountain?" he asked.
"No. From the other side of the morning."