Shonash Ravine

"Here. This spur that runs off the main line three miles out to Clayton Ravine. It's a long stretch of level track that will still exist in 1985. This is where we will push the DeLorean with the locomotive. Funny. This map calls Clayton Ravine, Shonash Ravine. That must be the old Indian name for it. It's perfect. A nice long run that goes clear across the bridge over the ravine - you know, over near that Hilldale housing development."

—Doc Brown at the railroad map in 1885

Shonash Ravine, later known as Clayton Ravine and even later renamed Eastwood Ravine, was a ravine to the south of Hill Valley. Carson Spur led directly to the ravine and for some time simply terminated at its edge. A railroad bridge was constructed across it in Summer 1887 that led to town, near the future site of Hilldale. On September 4, 1885, Doc Brown and Marty McFly

scoped out the ravine for a plan to return Marty to 1985. In the distance they heard the screams of the new school teacher Clara Clayton whose horses had gone amok after seeing a snake. Doc and Marty saved Clara from falling into the ravine, thus changing history.

After taking Clara to her house, Marty remembered from history class that the ravine was named after a school teacher that fell in there "a hundred years ago", that year, mainly because students wished that their teachers would fall into the ravine. In preventing this tragedy, the ravine remained Shonash Ravine until Marty's temporal displacement attempt on September 7, 1885, when it was thought he fell in with the train. By 1985, the ravine was then known as Eastwood Ravine, named after Marty's 1885 name, "Clint Eastwood".

Note: The following section is considered non-canon or is disputed in canonicity.

In the 1986B timeline, Citizen Brown has a secret lab near the Ravine (which became Clayton Ravine again). He kept the damaged Delorean there for safe keeping.

Non-canon or disputable information ends here.