swallow-hole

Now and then he passed by a deep dark swallow-hole, going down into the earth, as if it was the chimney of some dwarfs house underground; and more than once, as he passed, he could hear water falling, trickling, tinkling, many many feet below.

The Water Babies 2007

Now and then he passed by a deep dark swallow-hole, going down into the earth, as if it was the chimney of some dwarfs house underground; and more than once, as he passed, he could hear water falling, trickling, tinkling, many many feet below.

The Water-Babies Charles Kingsley 1847

Now and then he passed by a deep dark swallow-hole, going down into the earth, as if it was the chimney of some dwarf's house underground; and more than once, as he passed, he could hear water falling, trickling, tinkling, many many feet below.

The Water-Babies A Fairy Tale for a Land-Baby Charles Kingsley 1847

But how is the swallow-hole sure to end in a cave?

Madam How and Lady Why Charles Kingsley 1847