Br. R. L. Sherlock — Foraniinifera of Speeton Clay. 291 



are probably at least as numerous as those of all the other species 

 put together. Next in importance, numerically, is Crutellaria rotulata 

 (Lamarck), a species which ranges from Jurassic to Recent times and 

 has no stratigraphical value. The genus Cristellaria is relatively 

 very abundant, and this genus is characteristically Cretaceous. 



As the question of the Jurassic, or Cretaceous, age of the zone of 

 Belemnites lateralis, Phil., is unsettled,' it is worthy of note that three 

 of the seven species of Foraminifera from that zone are only known 

 from Cretaceous rocks; the other four having a wide range in time. 



The number of species in each genus represented in the Speeton 

 Clay is given below, together with the corresponding figures for 

 the Hils of Germany as given by Reuss (op. cit., p. 12). Reuss' 

 classification and nomenclature have been modernized to enable the 

 comparison to be more easily made. 



Genus. Speeton Clay of Yorkshire. Hils of Germany. 



12 

 2 

 4 

 7 

 13 

 22 

 1 

 1 

 1 

 1 



16 genera, 44 species. 13 genera, 67 species. 



In both deposits Cristellaria is represented by more species than 

 any other genus. The next best represented genus in the Hils, 

 however, is Vaginulina, but in Yorkshire only a few fragments have 

 been found, belonging to probably at least two species, although only 

 one has been determined. Nodosaria is about equally well represented 

 in both deposits, but it is remarkable that Lagena, which is fairly 

 common in Yorkshire, has not been recorded from the Hils. Another 

 noticeable difference is the presence of seven arenaceous genera in the 

 Yorkshire Speeton Clay, as against two in the Hils. 



Of the forty-four species from the Speeton Clay of Yorkshire, eleven, 

 or 25 per cent, are known from the Hils of Germanv. The presence 

 at Speeton of Rhabdogonium insigne, Reuss, of the well-marked 

 Cristellaria gracillissima, Reuss, both previously known only from 

 the Upper Hils, and of C. orhiculata (Roeraer), which Roemer 

 described from the Speeton Clay of Germany, but which Reuss did 

 not find, are interesting links between the deposits of the two countries. 



^ G. W. Lamplugh, " On the Subdivisions of the Speeton Clay " : Q.J.G.S., 

 vol. xlv, p. 589, 1889. 



