to qualify for a smilie you must have 30 Earthcache smilies. You will need to take your own pen to sign the log.
Earth-caches are usually in interesting parts of the country. They get you to take note of geological features around you. You don't need a PHD in Geology to complete an earth- cache but you do need to take your time to answer some simple questions.
I would not qualify for this but I am aiming for it. I will write a note when I hit the big 30