Erg (landform) and western Asia, and Central Australia. In South America, ergs are limited by the Andes Mountains, but they do contain extremely large dunes in coastal Peru and northwestern Argentina. They are also found in several parts of the northeast coast of Brazil. The only active erg in North America is in the Gran Desierto de Altar () that extends from the Sonoran Desert in the northwestern Mexican state of Sonora to the Yuma Desert of Arizona and the Algodones Dunes of southeastern California. An erg that has been fixed by vegetation forms the Nebraska Sandhills (). Sand seas and dune
Liwa (Arabic) Liwa (Arabic) Liwa, or Liwā’ (), is an Arabic term meaning ensign, or banner. The word has developed various other meanings in Arabic: "Liwa" was used interchangeably with the Turkish term "Sanjak" in the time of the Ottoman Empire. After the fall of the empire, the term was used in the Arab countries formerly under Ottoman rule. It was gradually replaced by other terms like qadaa and mintaqa and is now defunct. It is only used occasionally in Syria to refer to the Hatay Province, ceded by the French mandate of Syria to Turkey in 1939, at which time was