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LLANORIA AND THE LLANORIAN MOUNTAINS. About 250,000,000 years ago, according to some geological opinion, the Llanorian Mountains extended from the area of the present northern boundary of Texas, past the sites of present Dallas, Austin, and San Antonio, westward to cross the Rio Grande south of El Paso, and thence curved south and east past Monterrey, Mexico. An ancient land, termed by geologists Llanoria, lay to the east of the mountains and extended southward into the region now occupied by the Gulf of Mexico. The mountains were worn down by erosion, probably to a plain not very much above sea level and had probably sunk before Woodbine time. The land also sank into the present Gulf of Mexico.

Texas Almanac, 1949.

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Handbook of Texas Online, "Llanoria and the Llanorian Mountains," accessed November 19, 2017,

Uploaded on June 15, 2010. Published by the Texas State Historical Association.