Edgar Rice Burroughs 
Tarzan and the Jewels of Opar [EPUB ebook] 

In the forgotten city of Opar, the bloodied sacrificial altar of the Flaming God stood above vaults piled high with the gold destined for fabled, lost Atlantis. There La, the beautiful high priestess, still dreamed of Tarzan, who had escaped her knife before. Around her, the hideous priests vowed that he should never escape again. For now Tarzan was returning, and they were waiting for him. Tarzan planned to avoid La and the priests. But he could not avoid the earthquake that struck him down in the vaults and left him without memory of his wife or home — only with what memory he had had as a child among the savage apes who reared him.