Today the hole was extended horizontally to reach the main sewer line. I suspect that this location was where the main clean-out might have been before the remodel. It would have been just outside the house before the dining room was added.
A junction was removed and the fluid drained one bucket at a time. The camera went down that hole and made it about 1/2 way to the street before a blockage was found. The location was marked. Luckily for us the snake cleared the blockage. The line was reconnected so we have working plumbing this evening. Tomorrow the camera will be put down the line again to take a look.