1923 



CHRONOLOGY 



33 



TABLE III — JURASSIC CHRONOLOGY (Hemerse) 



ViRGATAL and Planulatal Epochs (pars) 

 (Kimmeridgian) 



H.S., H. Salfeld ; J.P., J. Pringle ; A.M.D.. A. Morley Davies 



Ages Hemerce 



Pseiidovirgatitan 



3. " pallasianus 



2. " lomottossovi 

 I. scriiposiis 



Strata 



1. Hartwell Clay, Ayles- 



bun% Bucks 



2. Crendon Clay, Bucks 



3. Kimmeridge, Dorset, 



Oil Shales (J.P.) 



Aulacosphinctean 



2. Aulacosphinctes 4. Chawley Beds, Berks 



I. " dorsoplaniis " 5. Shotover Xodule Bed, 



Oxon 



Mazapilitan 



2. Mazapilites b 



I. Mazapilites a 

 Gravesian 



7. irtKS 



6. gravesian a 

 5. steraspis 



4. hyhonota 



3. heckeri 



6. Symon Beds, Mexico 



7. Symon Beds 



8. Hen CUft" Beds. 



Kimmeridge, Dorset 



9. Hen Cliff Beds 



10. Solenhofen Beds, 



Bavaria 



11. Solenhofen Beds 



12. Solenhofen Beds 



2. politus (H.S.) 13. Wurtemberg, W.J. t 



I. hiplex siliceus 14. Wurtemberg, W.J. e 



(H.S.) 



Physodoceratan 



II. longispinnm 



15. Weymouth, Dorset, 

 Pudding Stones 



Some equivalents 



Swindon, " Portland 

 Sands " ? Russia, Vir- 

 gatites Beds ? 



Warren Farm, Stewklev, 

 Bucks (A.M.D.); Ring- 

 stead 31 (H.S.) ; Mo- 

 ra\"ia, Ignaziberg 



Tiddington, Oxon ; 



Stramberg Beds ; 



India, Chidamu Beds 



and Oomia group ; 



Mexico, Portl. inf. 

 Swndon, Wilts, Turner's 



Brickyard, upper clays 



(J.P.) ; Russia, Lower 



\'olgian (pars) ? 



Upper Mazapilites Beds, 



Mexico 

 Lower Mazapilites Beds 



Boulogne, Portl. c ; Wur- 

 temberg, White Jura f 

 Boulogne, Portl. d 

 \\'urtemberg, W. J. ( 



Upper Crusol Beds (H.S.) 



Upper Crusol Beds (Fon- 

 tannes) ; Middle Crusol 

 Beds (H.S.) ; Transyl- 

 vania 



Nattheim Beds {A. poli- 

 tnlus, Ouenstedt ?) 



Xattheim Beds {A. plan- 

 iilatus siliceus, Ouen.?); 

 Transylvania 



Ringstead Bav 30 ; Swin- 

 don (H.S.)'; Tidding- 

 ton, Stewkley, Ely, etc. 

 Aptychus ; Boulogne, 

 Kim. a ; \\'urtemberg, 

 W.J. f ; Italy, Mount 



