One (possibly unverified) assertion I've encountered is that "Springfield Mountain" is an old name for Wilbraham, Massachussetts. I think one of the versions in the DT appends a note stating that thesis.

Once when I had a job in the Mojave Desert I'd take desert strolls on my lunch hour. I never saw a snake, notwithstanding I was in the realm of the famous Mojave Green Snake, said to be somewhat less shy than other members of the same genus. So maybe the Timber Rattlers in MA aren't rare; maybe, like the dinosaurs in Dilbert, they're just hiding.

T.