THK CRETACEOUS SYSTEM 489 



guidance of Professor Kilian with regard to the succession and the 

 grouping of the zones. 12 The illustration, Fig. 166, is reproduced 

 IV. >in one of his sections. 



In this part of France there is a complete passage from the 

 marine (Tithonian) facies of the Jurassic to the Lower Cretaceous, 

 and the exact line of separation has been a matter of dispute, but 

 Professor Kilian has made it clear that the zone of Hoplites 

 Soissieri should be regarded as the first term in the Cretaceous 

 Series. The thickness of the several stages varies considerably in 

 different parts of the area, but the total is about 2000 feet, and as 

 it largely consists of limestones its formation must have occupied a 

 long period of time. 



The following is a tabular view of the succession in the M. de 

 Lure: 



f Marls with Bclemiiites semicanalicutus, Oppelia nisus, 

 ,. .. and Hoplites fur catus. 



SOo't^fiOO i Limestone of Graves with Toxaster Collegnoi, etc. 



Limestones with Ifojilites Deshaycsi passing into Orbito- 

 \ Una limestone with Jlcquienia ammonia. 



Barremian, f Limestones with recticostatus and Macroscaphites Yvan'i . 

 200 to 400 ( Limestones witli Holcodiseus fallax and Crioceras Emeriei. 



Hauterivian, 

 about 300 



Valenginiau, 

 600 to 1200 



Limestones with Hoyilites anyulicostatus. 



Limestones with Crioceras DuvaH, Hoplites radiatus, 



and Bel. dilatatus. 

 Marly limestone with Hoplites neocomiensis and //. 



regalis. 



Marls with Hoplites neocomiensis and Belemnites Emcrici. 

 Marls with Hoplites Boissieri, H. occitanicus, and Pkyllo- 



ceras semisulcatnni. 



The limestone with Requienia ammonina, classed above as 

 Aptian, is part of the special facies developed at Orgon in Vaucluse, 

 which was formerly regarded as the type of a stage called Urgonian 

 by d'Orbigny but since found to pass laterally into Barremian and 

 Lower Aptian. 



2. The Jura 



In this area the whole Lower Cretaceous Series is still purely 

 marine, but the thickness is much less, being only from 500 to 700 

 feet, and Ammonoids are much less common than they are in 

 the southern region, so that the same zones cannot be recognised. 

 According to the most recent authorities the following is the general 

 succession in the Eastern Jura and in the basin of the Rhone. 



. .. | Marls with Ostrea aquila and Plicatula placunea repre- 



4010*60 Dented at Perte du Klione by sandstones, underlain 



I by marls with Orbitolina lenticularis. 



T> ( White limestone with llequienia ammonia represented 



rennan, j &t per(;e Ju Rhone by red and . ii me8tone8 w i t h 



( Heteraster obhmjus and Het. Couloni. 



