30 CALCAREOUS ALGAE OF THE MIDDLE EAST 



species, whether preserved in limestone or marl, and there is normally no confusion 

 with the Valanginian species C. lucasi Emberger. 



Horizon. Upper Jurassic ; circum-Mediterranean and Middle East. 



Material. Numerous solid and thin-section specimens from Qatar Peninsula, 

 Persian Gulf, where it is abundant in the subsurface Upper Jurassic " Arab Zone " 

 (Fahahil and Qatar Formations : Sugden in press) probably of Kimmeridgian- 

 Tithonian age. Also at the same level in north-eastern Saudi Arabia (Powers 1962), 

 and in Gezira no. 1 well, Murban, Abu Dhabi, Trucial Oman. Associated micro- 

 fossils are the alga Salpingoporella annulata Carozzi and the microcoprolite Favreina 

 salevensis (Pare^jas). Thin-section material from both Kirkuk and Samawa, Iraq, 

 where it abounds likewise in the subsurface Najmah Formation, of about the same 

 age, with the same companions. Also seen in thin-sections from the topmost 

 Jurassic at Haushi, Southern Oman, Arabia, accompanied by debris probably 

 referable to Griphoporella perforatissima Carozzi, an alga initially described from the 

 Upper Portlandian and Berriasian of Switzerland. The species is common in the 

 Upper Jurassic of numerous exposures in southern Persia (Gollestaneh Coll.). 



Remarks. Clypeina jurassica is a common microfossil in the Upper Jurassic of 

 southern and central Europe, North Africa and the Middle East, and records of it are 

 very numerous. Described by Favre (Favre & Richard 1927) on thin-section 

 material from Switzerland, and re-described for comparison with Clypeina inopinata 

 (Favre 1932), the next advance was the description of Algerian material by Morellet 

 (1951) based on both thin-section and solid (silicified) specimens. Donze (1958a) 

 re-described material from the type-area from a good selection of solid specimens, 

 presumably isolated by weathering or artificial breakdown of weathered material. 

 For the present study of Middle East examples both numerous thin-sections and 

 solid examples obtained by washing of crumbled core-material have been available. 



The descriptions drawn up for this species by Favre, Morellet, Donze and myself 

 all differ slightly in detail. The principal difference is that specimens from the type- 

 area (Switzerland) show a lesser maximum number of sporangial tubules per verticil 

 than do those from some other localities. For Swiss material Favre gives a relevant 

 count of 10-17, an d Donze 7-17, whereas Morellet, with Algerian examples, gives 

 11-20, and the Middle East material (above), shows up to 24. Although there are 

 numerous figures in the literature of random cuts of this species conforming in this 

 particular with the type-material, there are some which indicate a higher count 

 (e.g. de Castro 1962, pi. 18 ; Italy, Naples area). These higher counts are from 

 more southern areas than that of the type-material. It would seem that this is a 

 case where the historical development of western Europe has resulted in the original 

 description of Tethyan material being made in a marginal area, a phenomenon 

 familiar both in stratigraphy and palaeontology. 



Other differences observed in the Qatar (Middle East) specimens were the some- 

 what variable convexity of the verticils, and the prominence of the central thickened 

 ring on the lower verticil surfaces. The former was however recorded by Donze on 

 topotype material, and indeed is to be expected from our understanding of the growth 



