B. Bullen Neivton — An Echinoidfrom Sinai. 441 



accumulation of the gravel, and unfortunately little more can be 

 said with confidence. 



The Ouse follows a serpentine course from the neighbourhood of 

 Sharnbrook to Bedford, a distance in a direct line of rather more 

 than six miles, and all the way the bed of the river lies practically 

 on the Great Oolite Series— the normal dip being locally counter- 

 acted by slight undulations and occasional faults. It is possible that 

 the small anticline may be connected with these earth-movements, 

 but as its direction is contrary to that of the gentle folds above 

 noted, this supposition does not appear to be probable. 



Again, it might be surmised that the flexure was purely local and 

 superficial, that perhaps glacial action had been the cause; but of 

 this there is no distinct evidence either for or against. All that cart 

 be reasonably inferred is that the superincumbent portions of 

 Kellaways Beds and Cornbrash — the latter but a thin band of 

 rock in the immediate district — had been planed off the dome prior 

 to or during the period of maximum glaciation, when the Boulder- 

 clay which crowns the adjacent plateau was laid down. The 

 erosion of the softer strata flanking the anticline was perhaps due 

 to the action of the river, if not to torrential waters in the later 

 phases of the Glacial period; and possibly the arch of Oolite 

 limestones stood out as a low ridge or islet in the broad course 

 of the river, until the inequality was levelled up by the accumulation 

 of the valley deposits. 



lY. — ZlXTBIA OBLONGA (OeBIGNY) FROM SiNAI. 



(PLATE XV.) 

 By E. Bullen Newton, F.G-.S. 



IN a collection of Cretaceous fossils from Sinai obtained by Mr. T. 

 Barron, F.G.S., which has been entrusted to me for determination 

 by the Geological Survey of Egypt, I found several specimens 

 of Linthia ohlonga, a form of Echinoid which appears to have escaped 

 the attention of modern writers on the palseontology of the Sinai 

 Peninsula. In tracing the history of this species it is ascertained 

 that d'Orbigny first figured and described it under the genus 

 Periaster during the year 1856 in the Pal. Frangaise Terr. Cretaces 

 Echinodermes, pi. 900, pp. 275, 276, where it is referred to as 

 having been collected by M. Lelebvre at Mount Garebe, near 

 Suez, from rocks regarded as of Turonian age, in association with 

 ^adiolites. 



Dr. Martin Duncan ^ next determined the species among Mr. 

 Bauerman's fossils from Sinai, which are preserved in the Museum 

 of the Geological Society of London. It was collected at Wady 

 Nagh el Bader (= Wadi Budra), Duncan listing it as one of the 

 commonest forms of the collection found in association with Badiolites, 

 and belonging to an horizon equivalent to the Cenomanian of France. 



i Duncan, P. M., "Note on the Ecliinoderniata, etc., etc., from the Cretaceous^ 

 Eocks of Sinai" : Quart. Journ. Geol. Soc, vol. xxv (1869), pp. 44-46. 



