650 MR. R. B. NEWTON ON [jSFov. I9II, 



such as Spain, Italy, etc., as well as Crete, where these large 

 NummuliUs were long ago determined by D'Archiac. 1 



The matrix containing this numniulite and oyster is much more 

 compact than the sandy-looking rock that contains the pectini- 

 form shells — regarded as of Aquitanian age : both deposits being 

 similarly localized yet furnishing evidence of different horizons^ 

 Ain Sciahat being the neighbourhood referred to, 



Pelecypoda. 



OsxRE.i sp. indet. 



Remarks. — -The specimen is a fragmentary oblong, smooth and 

 moderately convex valve, embedded in matrix, which has ap- 

 parently lost, through erosion or otherwise, its external layers, so 

 that only the polished surface of the inner structure of the shell is 

 now exposed. It is not possible, therefore, to identify such a 

 fossil, but from its general shape and very slight curvature of the 

 postero-dorsal region, it might have belonged to such a form as 

 Solander's Ostrea gigantea. which is distributed throughout the 

 Eocene rocks. 



Dimensions (approximate). — Length = 60 millimetres ; height 

 = 80 mm. 



Occurrence. — The matrix is a cream-coloured limestone con- 

 taining Nummulites gizehensis. 



Locality. — Plateau above Ain Sciahat. 



VII. Results. 



The fossil shell-remains from Cyrenaica prove the presence of 

 post-Pliocene, Miocene (Vindobonian and Aquitanian), Oligocene 

 or Uppermost Eocene (Priabonian), and Middle Eocene (Lutetian). 



The post-Pliocene fauna is similar to what is known in other 

 North African or Mediterranean countries, the presence of Cerasto- 

 derma edule in rocks situated some distance from the sea-board in 

 a solid limestone suggesting a more ancient facies than those 

 occurring in an actual beach-deposit nearer the sea. 



Such mollusca as Strombus cf. coronatus, Alectryonia cf. virleti 

 constitute reliable evidence in favour of the Helvetian -Tortonian 

 (Miocene) deposits being present in Cyrenaica, and forming part of 

 similar beds occurring in Egypt and other neighbouring countries. 

 The genera Amphistegina and Litliothamnion also occur in these 

 rocks. 



The abundant pectinoid shells found at Ain Sciahat with highly 

 ornamented costse, as well as the simpler forms found at Birlibah 

 and Wadi Umzigga, favour an Aquitanian horizon, more especially 

 as specimens from the last-named locality exhibit examples of 

 Lepidocyclina elephantine^ which is characteristic of Aquitanian 

 deposits. 



1 See V. Raulin, 'Note sur la Constitution Geologique de l'lle de Crete' 

 Bull. Soc. Geol. France, ser. 2, vol. xiii (1856) pp. 439-58. 



