County Road signs are entirely different and would be the Unsuitable for Motors blue sign, dead end sign or a small white disc with a black arrow saying County Road.
I think the sign maker has just left out the important "TO" before County Road.
As Brian says the sign says that the Footpath goes to the County road at Canonteign Barton.
The reference to the County road is the destination of the Footpath.
I can't recommend using the footpath through the mine over the arsenic laden spoil heaps and don't be tempted to ride your bike to the top of the spoil heaps because they are very loose as well as poisonous and the view isn't worth the effort.
There are a few interesting anomalies in this valley which date back to the creation of the now defunct railway and the also historic mining industry as well as the larger estate roads so don't believe every sign you see and keep asking questions. Some of the things which have dropped off the map over the years are quite interesting.
An interesting anomaly there because the footpath users divert onto the white road from Byteign lodge to Canonteign close to the Canonteign end rather than follow the recorded route of the footpath along the edge of the golf course. I have always viewed this white road as private and I believe it is signed as such at Byteign lodge but it is most certainly vehicular and the footpath has not to my knowledge ever been officially diverted onto the track so if the gate is not locked then there is no legal reason not to use it. Quite a dull track though. You will see that the way continues across the county road into the Canonteign estate where it is most certainly private.