Tex. Natural Resources Code § 11.015

(a) The boundary lines of all counties in the Texas Panhandle that border on the New Mexico boundary line are extended by extending the north and south lines of certain counties west to the Texas-New Mexico line, which was established by the survey of John H. Clark in 1859 and later retraced to completion on September 26, 1911, by the Boundary Commission composed of Francis M. Cockrell and Sam R. Scott, under authority of S.J.R. No. 124, of the 61st Congress, Third Session.

(b) The boundary line is referred to as the 103rd Meridian and is described as follows:

Beginning at the point where the one hundred and third degree of longitude west from Greenwich intersects the parallel of thirty-six degrees and thirty Minutes North latitude, as determined and fixed by John H. Clark, the Commissioner on the part of the United States in the years eighteen hundred and fifty-nine and eighteen hundred and sixty; thence South with the line run by said Clark for the said one hundred and third degree of longitude to the Thirty-second parallel of North latitude to the point marked by said Clark as the Southeast corner of New Mexico; and thence West with the thirty-second degree of North latitude as determined by said Clark to the Rio Grande.

(c) Copies of the deeds certified by the custodian of records in each of the counties in New Mexico in which the land is located and other instruments of title are admissible as evidence in suits filed in this state to the same extent as the original deeds or certified copies of them.

(d) The county clerk of each of the counties in Texas in which the land is now located may file the certified copies of deeds and other instruments affecting title in the same manner as the original deeds could have been filed.