Vacancies and Excesses
A vacancy is a tract of unsurveyed, unsold public land located between original surveys usually due to a surveying error. Because this land is unsurveyed and not included in the original land grant, it still belongs to the people of Texas and is therefore defined by the Texas Constitution as being for the benefit of the Permanent School Fund.
By contrast, excess acreage within a titled or patented survey is an amount of acreage greater than that called for in the original grant or patent. Just like vacancies, excess acres usually result from inaccurate surveying from the 1800s and early 1900s. A modern survey of an original grant of land may reveal excess acreage in a particular survey. Title to all or part of the original survey may be affected by the existence of the excess.