Although oil has been produced since 1908 from salt domes in the Emba area, which lies between the south end of the Ural Mountains and the north shore of the Caspian Sea, the geological situation in that region has escaped the attention of many American geologists. Salt-dome geologists of the Gulf Coast region have frequently had their attention directed to the salt structures of Germany and of Roumania, whereas greater resemblance to the Gulf Coast is to be found in the Emba district, where more than 100 salt domes are known in an area about the size of the Gulf Coast exclusive of South Texas. Future discoveries may bring the total to 300 or more salt domes, including deep ones. Only six domes are being exploited but many others have shown evidence of accumulations of oi and gas. Production has been found in "Permo-Triassic," Jurassic, and Cretaceous strata, but chiefly in Jurassic sands. The oil reserves appear to be commercially important but do not rank with those of the Gulf Coast.

The Emba mother salt series is of Permian age--probably Upper Permian. The overburden is much thinner than that of the Gulf Coast, consisting chiefly of Mesozoic strata, with local patches of Tertiary sediments, and a blanket of Quaternary (Caspian) beds in the coastal area.

Many of the shallow salt structures are larger than any Gulf Coast shallow domes. Future exploration will probably reveal an increasingly larger percentage of deep domes.

More is known about pre-salt strata in the Emba region than in the Gulf Coast because of the outcrops in the southern Urals. The Upper Carboniferous and Permian sections have been rather closely correlated by several investigators with the Pennsylvanian and Permian sections of the Mid-Continent region, largely on the basis of the ammonites contained.

Development has been slow in the Emba district due largely to the remoteness of the area, the long severe winters, and the thinness of the sands as compared with the prolific Tertiary sands of the Caucasus belt.

The tectonic setting of the Emba domes is discussed and compared with that of the salt domes of the Gulf Coast, of the North German basin, of Persia (Iran), and of the Carpathian foothills belt in Roumania.