The significance of the Lower Devonian of the Torkoz area
 was first highlighted by the discovery of a limestone unit
 with Sellanarcestes (HOLLARD 1960) which allowed
 biostratigraphic correlation over wide distances in the Dra
 Valley, with the area S of Akka, sections (Jebel
 Hamsailikh) S of Foum Zguid, and further on with the
 Tafilalt and Saoura Valley of Algeria.  HOLLARD (1963)
 briefly characterized the whole Torkoz succession in a
 column in his stratigraphic table of the southern Anti-Atlas.
 Further data can be taken from his diagrams of facies
 development in HOLLARD (1967: figs 8-10).  A detailed
 chart in HOLLARD (1 98 1) mentions the Rich Tamelougou as
 a sampled locality but this posthumous publication does not
 give further explanations.