CALCAREOUS ALGAE OF THE MIDDLE EAST 83 



of the branches : those of T. perplexa are spindly compared to the very swollen 

 primaries of T. radoicicae, where each branch takes proportionally more space and 

 hence there are fewer branches per verticil. 



This species is dedicated to Mme. R. Radoicic of Belgrade, Jugoslavia, as a tribute 

 to her many contributions to palaeophycology, and friendly correspondence with me. 



Genus TRIPLOPORELLA Steinmann 1880 



Diagnosis. Club-shaped calcified dasyclads with large stem-cell, close-set 

 verticils of numerous branches each consisting of an elongate cylindrical primary 

 containing sporangial bodies, and dividing into several thin hair-like secondaries. 



Remarks. The large and showy Triploporella spp. of the Upper Jurassic and 

 Cretaceous are curiously ill-represented in the Middle East material now studied. 

 No further material of Triploporella fraasi (Steinmann 1880 ; 1899) from the 

 Lebanese Albian has been examined : most of this author's descriptive detail came 

 from his Mexican specimens and not from the ill-preserved Lebanese fossils. Three 

 other Middle East records of the genus known to the writer are all Cretaceous, all 

 represented by very few random thin-sections, and none specifically determinable. 

 Two, from the Lower Cretaceous of Burum, Wady Hiru Basin, Hadhramaut, and 

 from the subsurface Garagu Formation (Valanginian-Hauterivian) of Makhul no. 1 

 well, Mosul Liwa, Iraq, are compatible in size with such a species as T. marsicana 

 Praturlon from the Italian Barremian-Aptian. The third, from the Qamchuqa 

 Formation (Aptian-Albian level) of Sarmord, Sulemania Liwa, Iraq, is much smaller 

 than any described species. 



IV. THE STRATIGRAPHIC SUCCESSION OF DASYCLAD ALGAE 



The stratigraphic ranges in the Middle East of most of the dasycladaceae described 

 in this work are set out in Fig. 6. Before discussing these in relation to the different 

 geological levels involved, the general reliability of the family for stratigraphic 

 purposes must be considered. 



Dasycladaceae are sessile benthos with well-defined coastal ecologic requirements, 

 the latter discussed below (p. 92). It is, therefore, rare for them to show the limited 

 substage range of an ammonite species, and they are inevitably influenced by facies. 

 Against this, the Tethyan coasts and shelf-seas furnished a long succession of suitable 

 habitats for growth and entombment, and dasyclad euryhalinity permitted frequent 

 proliferation in emergent areas when their abundance as microfossils matched that 

 usual with marine foraminifera, themselves scarce or banal under these conditions. 

 In the favoured area of the Middle East, therefore, (and this probably applies to 

 many other areas in the Tethyan belt), I have often found it possible to date to stage- 

 level by a consideration of dasyclads in association with other algae, and their 

 relative abundance (cf. Elliott, i960). Supplementary confirmation from other 

 fossils has been welcome, but rarely contradictory. 



A similar conclusion was independently reached by Praturlon (1966), for the Liassic 

 to Palaeocene algae of the central Apennines, Italy. It is of interest to compare the 



