1923 



CHRONOLOGY 



39 



Sequence VII (continued) 



Correlation 



Ringsteadian 

 hrandesi 



psetidocordatus 



Strata 



17. Sandy clay 



16. Ironshot Oolite 



15. Clay 



14. Clay 



13. Red, sandy limestone 



Fauna 



Rhynchonclla inconstans, 

 Ringsteadia pseitdocor- 

 datiis, R. hrandesi etc. 



R. pseiido-cordatiis 



R. pseiido-cordatits 



Seouenxe VIII— North Ferriby 

 East Yorkshire, a boring. Specimens submitted by Geological Survey of England 



Correlation 



Strata 



Prionodoceratan 

 superstes ? 

 prionodes 

 dichotomum 



1. At 23 to 26 feet down 



2. At 30-35 feet 

 Dichotomoceras sp. 3. At 50 feet 



Uncertain 

 Uncertain 



4. At 60 feet 



5. At 120 to 130 feet 



Fauna 



" Amoebocerates " and 

 Prionodoceras 



Dichotomoceras dichoto- 

 mum 



Dichotomoceras sp. 

 stouter than D. dicho- 

 tomum 



" Amoeboceras " sp. with 

 tine ribs and interca- 

 lated secondar\- ribs 



"Amoeboceras " 



One important point here is the position of Dichotomoceras not far 

 below Prionodoceras, a position confirmed in Scotland (see Seq. X). 

 The other important point is the repetition of " Amoeboceras " forms. 

 The earliest forms, some 100 feet below Dichotomoceras, seem to be 

 too far dovm to be later than Ringsteadian ; but they were not satis- 

 factorily identifiable with the true Amoebocerates of the WTiite Jura 

 a (Perisphinctean). Much time, however, will be required before all 

 the varied Amoebocerate forms can be worked out — there is too much 

 else claiming attention. 



A boring in Norfolk gave evidence of Ammonites superstes, Phillips, 

 below Rasenia stephanoides. This Ammonite is an Amoebocerate. The 

 Norfolk boring, therefore, takes the Yorkshire succession further up, 

 but see Scottish evidence, Seq. X. 



