14 



M.K. HOWARTH AND N.J. MORRIS 



Fig. 8 The main Jurassic cliff, central Jebel Billum: the peak of Jebel Billum consists of Palaeocene Limestone of the Umm-er-Radhuma Formation: the 

 vertical cliff in the foreground is formed by the Naifa and Hajar Formations, and is capped by the Qishn Formation (see Fig. 10 for detail). 



'^Mm^^^^m^k^^^i^-M^^^i 



Fig. 9 The type locality of the Naifa Formation at Naifa Cliff; most of the beds are the middle and upper parts of the Billum Member; the Kilya Member 

 is the highest cliff in shadow on the extreme right. 



Fig. 10 Detail of the main Jurassic cliff (at CJB on Fig. 7) on the southern side of Jebel Billum; owing to the difficulty of access, the exact position of the 



unconformity between the Kilya and Arus Members is uncertain. 

 Fig. 11 The Pcrisphinctid Cliff in eastern Jebel Billum (at PC on Fig. 7); most of the cliff consists of Naifa and Hajar Formations overlain by Qishn 



Formation at the top; Madbi Formation is exposed at the base of the cliff on the left, and perisphinclid ammonites occur low in the Billum member at the 



base of the cliff in the centre of the photograph. 



