Great responses so far. Minerals can be under a body of water (ie off-shore wells), but as pointed out who owns the rights thereto may be a difficult question. For example, "The permanent political boundary line between the states of Texas and Oklahoma along the Red River is the vegetation line along the south bank of the Red River except for the Texoma area, where the boundary does not change. " So Oklahoma’s territory may expand or contract based upon the vegetation line.