That sounds a little magical and at the least a little fishy, because normally if I find earrings, I find single ones, not pairs. (Naturally, I keep them; they're always costume jewelry.) In fact, a friend of mine who's an artist only wears single earrings she's found on the street. These are silver and well-made; in truth, there's almost zero chance they would have ended up with the person who lost them. (Sorry to burst your bubble.)
What should I have done with these earrings when I found them?
Left them for the rightful owner to find and cherish forever
Kept them—after all, finders keepers, and it's a busy street
Sold them for scrap because silver is over $35 and ounce nowadays
Donated them to Housing Works or other worthy charity
Other which I'll explain in the comments