Still not listening

Ok, let's back up. First they look at the map. Doc says that they obviously used the original name of Clayton(Eastwood?) Ravine(I don't remember what it was but it was a local Indian word). They then went horseback riding near Clayton Ravine, where they saved Clara Clayton from falling in. While riding back, Doc remarks that he was glad that he kept Ms. Clayton from falling into Clayton Ravine. He then realizes that history was changed after Marty told him the story about Clayton Ravine.(Sure Doc, every kid at school knows the story. We've all wanted to push a teacher in there. he he.) Also, to sidetrack ya, try to bear in mind that they're not going to find out what they change without some proof(ie picture, video, etc.) In other words, 1). Doc never said where the name came from; Marty said it. 2). The name on the Map was the old name before the change, 3). They saw the map before rescuing Clara and 4). Until Marty opened his big mouth and mentioned the story of Clayton Ravine, they would've kept on calling it Clayton ravine. Course, they'd have never known what its new name was until they returned to 1985, so it wouldn't have mattered too much.

In the future before Marty interferred...

Before Marty interferred, Clara Clayton *had* fallen in. So, in the present (1985), the ravine was calld Clayton ravine. Then Marty interferred, and it was called Eastwood ravine in 1985. Before eiter of them fell in, it had some indian name.

Heard wrong

When Marty and the Doc are looking at the map, it is labled SHONASH ravine (after a local Indian tribe or something). Marty points out that it is named SNONASH and not Clayton. He proceeds to describe how he was taught about this ravine in school. The Doc replies: "Great Scott!" because he has seriously altered history (as Clayton did not fall into the ravine due to their meddling). Interesting tidbit, though. Rather than retaining the name SHONASH in the year 1985, the name is changed to Eastwood ravine. (Marty is named Eastwood in 1885)

The correct history

In response to commenter 2732, who said that before Marty interfered, Clara Clayton *had* fallen in (to the ravine). Actually, in the *original* history, she had. But it was actually Doc's, not Marty's, interference in time that altered her fate. Remember, there are three different time lines involved: the original, before Doc went back (the one in which Clara falls into the ravine); the Doc only alternate time line (where Doc saves Clara, and where Buford kills the Doc); and the post-Marty time line which is shown in the movie. In the original time line, Clara dies, in the other two she does not. But it was initially Doc's interference which altered her future, not Marty's. \r\rAs for the name of the ravine, we have no idea what it was called since 1885 in the second time line. It may have remained Shonash, since no one (that we know of) was killed there. Obviously, according to the third time line, the locals believed the man they knew as Clint Eastwood (Marty) was killed there, and thus the ravine was renamed to Eastwood Ravine.