Where is this place at?
An oak tree with "X's" on it that would have any historical significance would have to be 300+ years old!! Texas has many oaks but there are only a few that are actually over 300 yrs old.
I have looked into the production of gold in Texas and it is scarce! Mostly in West Texas. I find little or no records of significant production in the areas in the tales. The Heath mine produced very little. Llano river does give up a bit of gold but it is really insignificant.
There are a thousand tales of 'treasure' but like one of the previous posters, I think most are pure 'tale'! Actual records, and facts do not support the story.