After another day, more progress.
And finally, we have it dug out all the way to the stone wall.
Once we have it dug out, we then go back and work on trimming it up so that it is straight down from the fence. One day got us about 2/3 of the way to the end, but that's enough to start pouring cement.
Straight down the fence, all the way to bedrock.
Now we can frame it up with our standard pieces of Masonite sheets using 1 x 4 wood pieces to separate it from the fence, and then using compost and mulch bags to hold it all in place.
This first part took 15 bags of 60-pound Quik-crete and 2 and a half hours to mix and pour.
Now we can dig out the remainder while this sets up. Then we can remove the framing and move it down to the remaining section.