Got this info and photo from the Bushwalker magazine Volume 32, Issue 3, Winter 2007
“The Jump Back Pass or the ‘one in four’ road off the end of McMahons Lookout (Bimlow Topographic Map) was a key access for the residents of the Burragorang Valley. The 1930’s picture is from the John Hollingdale collection. The car is a 1930 Model A Ford.”
….and here’s another one from the Camden Historical Society collection. I am wondering now what reasons this road was built and why people used it.