JURASSIC AND LOWER CRETACEOUS OF WADI HAJAR 



AL MA'ABIR & JEBEL BILLUM 



11 



Naifa Formation 



UPPER STORM BED 



MIDDLE STORM BED- 

 (Al Ma'abir only) 



LOWER STORM BED' 



Erymnoceras jarryi (Douvlll6) (21 

 Eligmus aualites Horizon 



MADBI FORMATION: 



Brachiopods abundant, including 

 Somalirh ynchia. Micro th yridina, 

 Conarosia, Avonithyris, Bihenithyris, 

 Cereithyris, Dissoria, Eurysites 



Molluscs abundant, especially: 

 Deltoideum, Nannogyra, 

 Actinostreon, Neocrassina, 

 Indogrammatodon, Proconulus 



Perisphinctes IP.) sp. indet. (8) 

 Microthyhdina farquharsoni Muir-Wood (105) 

 Modiolus cf. bipartitus (J. Sowerby) 

 Deltoideum delta (Smith) 

 Nannogyra fourtaui (Stefanini) 

 Actinostreon aff. solitaria (J. Sowerby) 

 Neocrassina aff. unilateralis (J. de C. Sowerby) 



-Echinoids, Daghanirhynchia 

 -Shelly layer 



Perisphinctes sp. indet. (2) 

 Peltoceratoides sp. indet. (1) 

 Indogrammatodon egertonianus (Stoliczka) 

 Proconulus arabiensis (Newton) 



Somalirhynchia abundant 

 Indogrammatodon egertonianus (Stoliczka) 

 'Posidonia' somaliensis Cox 

 Nannogyra fourtaui (Stefanini) 

 Proconulus arabiensis (Newton) 



NAUTILOID BED, with 

 Paracenoceras meridionale Tintant 



Ripple marks and 'Iron Pans' 

 Erymnoceras cf . /a/r// (Douville) (1) 



UPPER SHUQRA: 

 Somalirhynchia abundant 

 Molluscs abundant, including 



Eligmus aualites (Stefanini), E. humei (Stefanini) 



Nannogyra fourtaui (Stefanini) 



'Gryphaea'balli (Stefanini) 



Actinostreon solitaria (J. Sowerby) 



Ceratomyopsis somaliensis (Weir) 



Ceratomya cf. wimmisensis (Gillieron) 



Bucardiomya somaliensis (Cox) 



B. aubreyi (Douville) 



MIDDLE SHUQRA: 

 Somalirhynchia appears, also 



Bihenithyris & Cererithyris 

 Shuqraia, corals and many molluscs, including 



lAntiquicyprina sp. and INerinella sp. 



LOWER SHUQRA: 

 Daghanirhynchia characteristic 

 Many Molluscs, including 

 Protocardia (Tendagurium) buckmani 

 (Morris & Lycett) and 

 Homomya cf. gibbosa IJ. Sowerby) 



Kohlan Formation 



Fig. 6 Vertical section of tfie Shuqra and Madbi Formations in central Jebel Billum and from 0.6 km SE of the Al Ma'abir road/river crossing to 1 km 

 eastwards; thicknesses of the Madbi and the Upper Shuqra are taken from the Jebel Billum section, while thicknesses of the Middle and Lower Shuqra 

 are taken from the Al Ma'abir area; the Madbi Formation below the Middle Storm Bed is faulted out at Al Ma'abir 



