466 Dr. F. A. Bather — Distribution of ' Terebella' cancellata. 



IV. — The Distribution of ' Terebella ' cancellata. 



By Dr. F. A. Bather, F.B.S. 



(Published by permission of the Trustees of the British Museum.) " 



I FJ1EREBELLA ' cancellata was the name given to some supposed 

 worm-tubes from the Cenomanian of the East and South-east 

 of England, in the Geological Magazine for December, 1911 (p. 553, 

 pi. xxiv, figs. 3-5). The chief feature of the species is an obscure 

 cancellate ornament formed by transverse and longitudinal folds. 



At that time these fossils were recorded from the Holaster 

 sabglobosus and Actinocamax plenus zones of the Cenomanian. The 

 only exception was the British Museum specimen A 1638 from the 

 Upper Greensand (Albian) of Betchworth, Surrey. Some other 

 horizons can now be added. 



Aptian: Specimen A 1702, collected from the Lower Greensand 

 of East Shalford, Surrey, by Caleb Evans. 



Turonian : a specimen submitted in June; 1917, by Mr. BI. C. 

 Brentnall, of Marlborough College, and obtained "just N. of the 

 main road over Overton Hill and S. of the short stretch of Roman 

 lload, just W. of the 4th milestone. On the 6 in. map, Wiltshire, 

 Sheet XXVIII S.W., the actual shallow excavation is shown under 

 the word Tumuli ". This is probably the " small pit " in the Chalk 

 Hock, zone of Holaster planus, mentioned on p. 197, par. 5, of Mem. 

 Geol. Surv., Cretaceous Rocks of Britain, Vol. III. 



Lower Eocene, Thanetian : Specimens A 1936 - A 1940, collected 

 by Captain P. R. Lowe, R.A.M.C., in July, 1917, from the quarries 

 near Wizerne, on the south side of the River A a, near St. Omer. 

 The matrix is a soft, friable, glauconitic sandstone, of a pale yellow 

 colour. Among the associated fossils are internal casts of Thracia 

 and of a Pholadomya, probably P. Tconincki (fide R. B. Newton). The 

 map of the French Geological Survey applies the name Sables de 

 Bracheux to this outcrop, but the fauna is not that of the type- 

 locality. In some of the specimens the cancellate ornament is well 

 denned, and in A 1939 the lines run diagonally (compare op. cit. 

 p. 551, line 4 from end, and fig. 4). 



The first point brousrht out in this note is the extended range in 

 time of Terebella cancellata from Aptian to Thanetian. 



The second point is the constant association of this form with 

 a glauconitic facies and a fauna relatively rich in mollusca. 



V. — Iceland — a Stepping-Stone. 



By E. B. Bailey, M.C., B.A., F.G.S. 



1. Introduction. 



WHEN in 1897 Sir Archibald Geikie published his important 

 monograph on the Ancient Volcanoes of Grreat Britain he 

 devoted chapter xl to a description of Iceland — so largely does our 

 North Atlantic neighbour bulk in the eyes of British vulcanologists. 



