Geology and Minerals
The Grand Erg Occidental, (also known as the Western Sand Sea), Arabic العرق الغربي الكبير (al-ʿIrq al-Ḡarbī al-Kabīr), is an erg in the northern center of the Algerian Sahara. It is the third largest erg in Algeria after the Erg Chech and the Grand Erg Oriental.
Geology of Arizona.
Cleveland Ironstone Formation.
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