THE GEOLOGY OF EGYPT. 399 



tria, etc., so that the Carboniferous age of the deposit is 

 unquestionable. But Schellwien (22) has recently under-, 

 taken a re-examination of the specimens, and comes to the 

 conclusion that they belong" to the Upper Carboniferous. 

 He finds two species of Enteles \Enteletes\ a species of 

 Spirifer allied to S. mosquensis, and other forms character- 

 istic of the Russian facies of the Upper Carboniferous. In 

 fact, according to Schellwien, there is not a single species 

 present which is confined to the Lower Carboniferous, 

 while there are several which have never been found except 

 in the Upper Carboniferous. 



However this may be — and the occurrence of Enteletes 

 is strong evidence in favour of Schellwien's views— the fact 

 remains undisputed that a part of what was formerly known 

 as the Nubian Sandstone in the Wadi Araba, is of Carbon- 

 iferous aee. The bed in which the fossils were found is 

 succeeded, without any apparent unconformity, by marls 

 and sandstones which are themselves regularly overlaid by 

 undoubted Cretaceous beds with Exogyra. Some fifty 

 metres above the Carboniferous fossil bank there is a red 

 sandstone which contains Araucarioxylon. 



Walther divides the whole of the old " Nubian Sand- 

 stone " of the Wadi Araba into three groups : — 



1. 100 m. of sandstones and marls which are pre- 



Carboniferous [or in part Lower Carboniferous]. 



2. 20 m. of marl and limestone which must be referred 



to the Carboniferous Limestone [to the Upper 

 Carboniferous]. 



3. 200 m. of sandstone which may be considered as 



the equivalents of the Permian, Trias, or Jura. 



In Syria and the Sinaitic peninsula also the Cretaceous 

 is underlaid by a sandstone which is generally known as the 

 Nubian Sandstone ; and below this at one or two localities 

 there is a limestone band containing Carboniferous fossils 

 (3, 14, 29). The limestone is itself underlaid by another 

 group of sandstones and conglomerates. The sequence, 

 therefore, is precisely the same as in the Wadi Arabi. 



By many writers the term Nubian Sandstone is now 



restricted to the part of the series which lies above the 



28 



