Ok, so you like Riverside State Park, yet you're complaining about people who don't pick up horse droppings? Who in their right mind would stop, get off of their horse & pick up droppings just to keep another person from complaining. It is a state park remember? Dog crap is obviously easier to take care than cleaning up after a 1000 pound animal. A trail isn't a corral. Duh? Take your bike & go ride on any state park trail country & then complain about horse crap. I'm just trying to say, your complaint is ridiculous. You are clearly city minded & don't have enough common sense to know you're an idiot.