Yes, that looks like a nice die crack through the bottom of the bust through 'ER' of QUARTER to the rim. Nice find! I doubt that die struck many more coins before that part of the die broke off.
I know this is an old thread but I thought I'd share mine that has the same die crack. I learned about today on the site. Mine has some missing letters also.
I have the same quarter. The die crack continues through the edge of Washingtons bust through the initials and on mine the die crack looks as if it ends at the hair.