CORRELATION OF THE JURASSIC 659 



rent into the Pterocerien, the equivalent of the English lower Kimme- 

 ridgian clay, and the A 7 irgulien, 26 marking the horizon of Aulacoste- 

 phanus pseudomutabilis and A. eudoxus (see table, page 655). In 

 Germany it is not uncommon for writers to divide the Upper Jurassic 

 into three stages — the Oxfordian, Kimmeridgian, and Portlandian — 

 using Oxfordian in a broad sense equivalent to the English Oxford 

 Oolites. 



In 1893 Choffat 27 introduced the formation name Lusitanian for the 

 lower Malm of Portugal. The series of formations exposed in the region 

 around Torres Vedras, north of Lisbon, rests upon strata of Callovian 

 age and is succeeded by Kimmeridgian beds corresponding to the 

 Pterocerien of France. The Lusitanian beds contain fossils characteris- 

 tic of the zones of Peltoceras transversarium and P. bicristatum and a 

 few which, elsewhere in Europe, range into the zone of Streblites tenui- 

 lobatus. They thus correspond essentially to the Argovien, Rauracien, 

 and Sequanien stages on the Continent and to the Corallian of England. 

 Therefore the geographical name Lusitanian may appropriately be used 

 to replace the lithological name Corallian, as Haug 28 has suggested. The 

 Purbeckian should be regarded as a substage of the Portlandian (sensu 

 lato), since it is only a fresh-water phase of the latter which, on the Conti- 

 nent, is represented by a complete marine series. 



If we incorporate these changes and substitutions, we arrive at the 

 following subdivisions for the marine Middle and Upper Jurassic of 

 western and south central Europe : 



Upper Jurassic. < 



Middle Jurassic,*; 



Portlandian, 



Kimmeridgian. 



Lusitanian. 



Oxfordian. 

 Callovian. 

 Bathonian. 

 Bajocian. 



This is the subdivision adopted by Haug (1908-11) and appears to be 

 the one most strictly in accord with the historical development of the 

 naming of the formations in England. Furthermore, it does away with 

 the objectionable lithological names, Oxford clay and Coral Rag, or 

 Corallian. 



20 Proposed by Tliurmaiin. 



27 Paul Choffat : Description de la Fauna Jurassique du Portugal. Classe des Cephalo- 

 podes. Premiere serie : Ammonites du Lusitanien de la Contres de Torres- Vedras. Lis- 

 bonne, 1893, 82 pp., 20 plates. (See p. 1.) 



28 E. Haug : Traite de Geologie, 1908-11, p. 1045. 



