Na és ezen is érdemes elgondolkodni, EZ tényleg hiba, nem úgy, mint amiken mi rágódtunk régebben...

(http://www.movie-mistakes.com)

Doc's tombstone was placed by his "beloved Clara". However, that was discovered (and carved) before Marty went back and changed the past by him and Doc rescuing Clara. So how did Doc meet Clara without Marty being there, given that the ravine was already called Clayton ravine, meaning that by definition she must have fallen in? Bit of a paradox, methinks. Even assuming he met her at the station, then after that her carriage fell into the ravine, the timings just don't work at all - she couldn't have fallen for him in minutes, and/or couldn't have had her name on the gravestone given that she fell in the ravine before Doc was shot.