Frog Identity?

I tried to identify what kind of frogs we have, from the following website, but none of them look like what we have.
http://www.nwf.org/frogwatchusa/frogs_state.cfm?showstate=va#frogs
The closest thing is the Green Frog, Bronze subspecies, except our frogs are dark brown or black and smooth. I didn't think they had any spots either. When they hear me coming, they go "MIRP!" and dive in the pond. I found a dead tadpole yesterday, but I guess that's not too unusual considering I had already found 2 other dead ones. Plus the rest of them were still swimming around so I guess the deck stain didn't do too much damage, if that's even what killed the tadpole.