An internet search didn't reveal anything about this monument. There is only one fountain in Rittenhouse Square Park (which is Neptune's head, read more here: https://www.inquirer.com/news/philadelphia/rittenhouse-square-history-fountain-turned-on-20190705.html) and it doesn't have its own POI as of now, so I'm assuming this is for that fountain. I've moved this POI accordingly and am closing this note.