That bike was in the TRASH?! Good grief, the things people throw away... I'm not even that big into girls' bikes, and even I would have been happy to take that one home with me. I can't say I know much about the bike you found, but it's definitely uncommon, at least to me anyways. What are your plans for it?
It's Snyder made, going by the dropouts and chain ring and a couple other features. They went out of business (Rollfast) in the early 70's, then Mossberg made Rollfast bikes. Yours has late 60's features, like the rack, seat, and pedals. There's no BMA6 decal on the seat tube which was required starting in 1971. My serial number list for Snyder doesn't match up to it, it should have a letter, followed by numbers.