That you are keeping the frog trapped in a bowl with water and rocks concerns me. The frog is most likely under a great deal of stress. As for the species, a picture would help to identify it. It could be a bullfrog. Look at this link to identify the species http://www.new.towson.edu/herpetology/Amphibians.htm . You need to either set up a proper terrarium for this frog if you are planning on keeping it, or please release the frog where you found it.