Abandoned well near a farm house story

A pair of tourists were out in the fields when they discovered an abandoned well near an old farm house. Of course they're curious so they drop a small stone into the well, but they never hear it hit bottom. They search and find a larger rock and drop it into the well but once again hear nothing. They decide they need something larger and search the farm yard for a larger object. After much struggle, they manage to drag a large railroad tie to the edge of the well and drop it over the edge. After several seconds, a goat tears across the yard and without any hesitation, dives head first into the open hole. The two tourists stand in amazement. About then a farmer appears and tells them he is looking for a lost goat. The tourists tell the farmer about the goat diving into the well. "That couldn't be my goat", the farmer replies, "My goat was grazing in the field roped to a railroad tie!"