The magic circle is used to hint at the fertile spirits cave, that said there has been a lot of confusion so I may look at adjusting that. Once cave is full of ice, it is the only place in the game to collect ice. The final cave has mushrooms (don't eat them...) and truffles. The statues were part of an early design to reward the player based upon their pregnancy progress but I eventually abandoned it since it was a bit complex. The eyes on the statues however should glow brighter the larger your pregnancy becomes.