A City in the North — Marta Randall

Warner Books, 1976. Paperback original, second printing 1979. The author's second novel. "Toyon was a Terran, powerful in his own sector of the galaxy, but here on the planet of Hoep-Hanninah he was a tourist who did not speak the language. Toyon was a brilliant man but to the ape like expresionless natives of this planet, he was a threat Toyon had a dream he was determined to realize; to travel to the ruined city in the north and explore it. But the Hanninah were as determined to thwart him; for in the path of his exploration to the ruins lay the secret of their survival."