That's definitely a cow nose in the photograph and it's also a cownose in Tazman's link. All the ones I've caught or seen in the Chesapeake and Delaware Bays were a dark brown on top. It's possible that they have lighter skin where the bottom is all sand. I know skates are a lighter color. The common skates in the northeast and mid-atlantic are the clearnose and the barndoor. I never ate a skate but I tried to eat a cow nose once. The meat was stringy. I froze it but it got freezer burned. I used it for crab trap bait. I release them all now. The ones we used to catch in the Chesapeake were all at least 30-40lbs. I think you probably caught a skate. Be careful with skates as they have areas on their skin that can cut you.
Here's a clearnose skate.
