Where is Marble Canyon off road trail?

I've heard a lot about an off-road 4x4 trail called Marble Canyon but it seems to be a big secret and nobody will post the actual location of the trail.
I know that it's somewhere around Silverwood lake or Hesperia Lake and some people call it "The Bar Trail".
Does anybody know what the actual location of Marble Canyon or The Bar Trail is??

More on the 1969 Inland Empire flood

Over the years there have been several floods in the IE. The most famous is the 1969 flood. In 1969, Day creek flooded down Haven ave running over 12 feet deep for the entire length of the highway. And Archibald, up above Hillside was in full flood. The Damn at the head of the canyon broke and all of the mud and debris either flowed down through the Horse Shoe Canyon and down Archibald or joined the raging Cucamonga Creek.