Children of Tomorrow

Children of Tomorrow by Arthur Leo Zagat - They roamed the vanished world that yesterday was America.
""Dikar," Marilee said, low-voiced.
"Of all the day between sunrise and sunrise, I am most happy in this quiet hour just before bedtime." Lying on the grass beside him, the warmth of her love enfolded Dikar like the warmth of the fire behind them and the scent of her in his nostrils was sweet and clean as the breath of the woods that enclosed the wide, long clearing. "I am so happy that I'm afraid," Marilee went on. "Something out there in the night hates to see me so happy."
This is one of the original pulp fiction stories.