earthen floor repair - water swelling

There is a spigot in the corner of a room with an earthen floor, which was unknowingly leaking for a time (perhaps a couple weeks), and it caused that area of the floor to puff up a great deal. Any input on how to fix it?

Cut out a nice clean square and replace it with flagstones or patio blocks underlaid with gravel.

 Be sure that the gravel goes deeper than the rest of the cob floor. This will allow any future leak to dissipate,  just as happens with a French drain outside.

Sylvia, Dale's advice is spot on...without exception. Earthen floors do not like water, and for this reason such things as any metal that can sweat is a big "no no." Any place there is such things, a buffer must be created.

Even some stones themselves are not good choices as they can also "sweat" during certain seasons to cause similar issues. Try for a large grained sandstone, blue stone, or other related "granular stone" that has large voids in its macro/micro interstitial structure. These tend to always stay dry and/or not "sweat" as they have a larger water capacity than other stones...

I had a similar problem with water having leaked on my floor. I felt so dumb when it happened because I did think it could happen but I came home after a long holiday and realized it had leaked.