What is "round-bottomed"

Usage examples of "round-bottomed".

As they rode up through the Vale of Eden, she pointed to him small, narrow valleys with their becks that fed into the round-bottomed Eden Valley.

It was big, taking up the major volume of the round-bottomed chamber-the deck on which he presently stood was no more than a small platform mounted over the stout longerons and curved hullmetal plates that formed the underside of the module itself.