We dug all the dirt out of the pit north of the raised bed, resulting in a trapezoidal hole 12 feet wide and between 11 and 13 feet long.
Now we need to remove the rock, so that the pit is deeper. At the shallow end, it is only about 8 inches deep; we want it to be about a foot and a half. This requires removing a layer of rock from the pit. We are assuming that, as with the rest of the yard, the rock in our yard is layered, and we can remove just the top layer or so to get the depth that we want.
On Thursday, we used the jackhammer to start breaking the rock up, using what appears to be a natural fracture running diagonally across the pit. This works pretty well, and in the first day's work, we extract two large rocks, and a big pile of smaller ones in the corner of the pit.
We still have to lift one of the big rocks out of the pit, separate the smaller rocks from the dirt and move the rocks and dirt out of the pit.
We spent all day Friday lifting the rock out of the pit and cleaning up. Then on Monday, we went back to breaking up the rocks with the jackhammer. Tuesday was (a) moving the rock around to the driveway, and (b) moving the dirt over to the dirt pile.
On Wednesday, we were able to just use the pry bar and grubbing hoe to loose the rocks and take them around front. After moving the dirt to the dirt pile (and mixing it with leaves), we had a complete ditch from one corner of the pit to the opposite corner.
Thursday, we used the jackhammer to break up the smaller corner and start on the larger one.
And Friday was just hauling all the rock out of the pit and out to the front of the house.
This left just the one corner with rock. Using the jackhammer, we broke it all up.
And we then took it around to the drive way, leaving us with a level, empty pit.
This took another week, so the rock extraction from this pit took about a month. As long as it is empty, we need to think about how to finish it off, before filling it back up with dirt.