Kids love collecting rocks, among other things, so it isn't unusual for them to pocket a few while the family visits national parks, not knowing that park rules prohibit this practice.
One child who recently took a rather large rock from Santa Cruz Island of Channel Islands National Park decided to return it, probably prompted by the parents to do so.
The letter was written anonymously–perhaps to avoid repercussions?—and was posted on the Channel Islands National Park Facebook page.
The Channel Islands National Park wrote:
"Take only memories, leave only footprints. Recently a very honest child (and possible future park ranger!) followed the national park's ‘no collecting’ regulation and returned a rock in the mail that was taken from Santa Cruz Island. It's never too late to do the right thing."
This episode reminds us of the kid who returned two small twigs to Yosemite National Park earlier this year. That postage was no doubt cheaper than this rock.