656 REPORT— 1891. 



horizon which, containing a fauna distinct from the Humphriesianus-zoTie, may 

 therefore be known as the Cadumensis-zone. 



The strata above this horizon have usually been called ' Parkiiisotii-zone.' There 

 are several objections to this name ; and the strata are capable of more subdivision. 



The bed at Halfway House, which yields the large Parkinsonia;, is superior to 

 the Cadomeiisis-zone. It may be called the Truellii-zoue. At the top of the lime- 

 stone of the Broad- Windsor district ;S^e/j/ir«i. s«^sni7, and species of Morphoceras are 

 found : and this is a still higher horizon (Zif/zafj-zone). Just below the Fullers' 

 Earth of this same district, in the Fullers' Earth itself of Eype, but in the upper 

 white limestones (about 25 feet thick) of the Bradford-Abbas district, are found 

 Oppelia fusca and other species indicating a still higher horizon. It is suggested 

 that the white limestone of the Bradford-Abbas district is contemporaneous with 

 the so-called ' Fullers' Earth clay ' of Eype. This horizon may be called the zone 

 of Oppelia fusca ; and whether this zone belongs to the Inferior Oolite or to the 

 Fullers' Earth depends on whether the observer be regarding the limestones of the 

 Bradford- Abbas district or the clay of Eype cliff. 



Several Continental geologists, however, commence the Bathonian with the 

 Cadotnen^is-zone. To this idea the presence of Farkimonice and other facts give 

 •considerable support. 



6. Notes 011 the Polyzoa (Bryozoa) of the Zones of the Upper Chalk. 

 By Geoege Robert Vine. 



In the jear 1867, in a paper on the Lincolnshire Wolds,^ Professor Judd 

 remarked that ' the time has uot yet come for separating the great mass of the 

 chalk-l'ormation in this country into zones characterised by their peculiar 

 assemblages of organic life. Indeed, such a task has not yet been accomplished in 

 the case of the best-explored districts of the chalk, except in a very imperfect 

 manner.' Since these sentences were written the task has been attempted, and to 

 some extent accomplished, but much still remains to be done by specialists. 

 The present paper, however, deals with the polj'zoa only, and with those of the 

 Upper Chalk particularly. 



In 1870, Mr. C. Evans'- gave a section of the Surrey Hills from Croydon, 

 through the North Downs to (,)xted, in which he shows the following succession 

 for the Upper Chalk : — 



■g /"Zone with Micraster-cor-anfjuinuin .... Parley beds. 



^ \ „ „ „ „ testudinariuiii . . . Kiddlesdown beds. 



g ( „ „ Holaster pla/nus ..... Kenley beds. 



In 1875, Dr. Charles BarroiB, in his ' Geology of the Isle of Wight,' established 

 four pala3ontological divisions of the Upper Chalk, based on the stratigraphical 

 divisions of Bristow, Ibbetson, and Whitaker :— 



Feet. 



Zone with Belemnitclla nmcronata 265 



„ „ Mici-astei--cor-anguimi,m 525 



„ ,, „ cor-testudlnariuin 165 



„ „ Holaster I'lanus ........ 65 



In the neighbourhood of Margate we have, according to Whitaker and others, 

 the following : — 



Zone of Micraster-eor-anguiniim Margate. 



,, „ eor-testudinarlum .... Ramsgate, &c. 



„ Ilolaster 2)lamis ....... St. Margaret. 



In Buckinghamshire and Cambridgeshire only the base of the Upper Chalk is 



represented :— 



Zone of Micraster-cor-Jjofiit .... Upper Chalk with flints. 





' Quart. Journ. Geol. Soc. vol. xsiii. p. 235. ^ Proc. Gaol. Assoc, for 1870. 



