Slimy Cave
The Slimy Cave is where Ruggedo orders captives locked away in his underground kingdom.
First named in Tik-Tok of Oz, ch. 16
"Guph," said the King in an agitated voice, turning to his General, "let us destroy this rash mortal at once! Seize her and take her to the Slimy Cave and lock her in."
Where this is
placed Beyond the desert worked out
read out of the chapters cited on this page, not stated in any one sentence of them
It's Ruggedo's prison cell inside his Nome Kingdom caverns, beyond the desert.