280 



as yet even mentioned in Yorkshire, I have drawn up a 

 short catalogue of the contents of the deposit, as far as I 

 have yet traced them. 



In the Bridlington Deposit occur : — 



Foraminifera... 1. Rotalia f Probably derived by watery ac- 



2. Textilaria... tion from the adjoining chalk. 



Infusoria. 



Pyxidicula ? 



Gaillonella varians Also at Bann, Ireland. 



Navicula phoenicenteron „ „ 



„ inequalis „ „ 



„ viridis „ „ 



» gibba „ „ 



,j indeterminate At Berlin. 



Cocconema lanceolata At San Fiora. 



Bacillaria vulgaris 



Campilodiscus zonalis * „ 



Eunotia diadema „ 



„ serra At San Fiora and in Hanover. 



Synedra ulna Also in the Polierschiefer. 



Fig, 8 represents the Campilodiscus zonalis, found fully 

 inflected, as some of the specimens of Campilodiscus clypeus 

 occur at Egra. Fig, 9 shows its expanded discoid aspect, 

 when the inflection is slight, but easily made evident by a 

 proper management of the microscope. The radii (if they 

 may be so called) are symmetrical to two axes, which may 

 be compared to the equator and a central meridian, in the 

 common projection of the sphere, the seeming radii being 

 slightly comparable to the terminal parts of the arcs of 

 latitude in this projection. In very favourable lights, con- 

 centric striations may be detected crossing these ribs, and 

 there is some appearance of punctation on the outer edge. 

 In other cases, the ribs seem nearly smooth or delicately 

 punctated. This may arise from the different character 



* See Figs. 8 and 9. 



