Who owns the minerals under county roads in Texas?

I realize the State owns the minerals under State Highways and they are listed on the plats as well. What about the county roads? Do the land owners on each side of the county roads own the minerals to the middle of the road?

Dear JBBR,

Everything depends on the type of document that created the road priveledges, and the nature of the language in the deeds to determine if the strip and gore doctrine applies in that particular case. Can't make a blanket statement for your question, even to its application in state highways.