sentences:  The park opened on April 15, 1976 and is named after Thomas F. McKinney, a businessman, race horse breeder and rancher, who owned and lived on the land in the mid-to-late 19th century.The park is part of the El Camino Real de los Tejas National Historic Trail.During the Cretaceous Period through the early Paleogene Period, much of Texas was covered by a shallow subtropical sea.