88 MIDDLE ALBIAN STRATIGRAPHY 



Middle Albian appear and thicken southwards. Deposits of lyelli Subzone age, 

 although no longer exposed, are present in this area. Buvignier (1852 ; 525-6 & 

 pi. explanation p. 45) lists lyelli Subzone fossils from as far N. as Clermont-en- 

 Argonne, 31 kms NNE. of Revigny-sur-Ornain. These include Pseudhelicoceras 

 argonnenis (type locality), Brancoceras versicostatum and Lyelliceras lyelli (although 

 he states on p. 521 that the only locality at which this species had been found was 

 at Senard about 17 kms a little E. of N. of Revigny-sur-Ornain). From Revigny- 

 sur-Ornain itself, and, in the case of the last-named species below, between here and 

 Mussey (presumably from the excavation for the Marne-Rhine Canal) he records 

 Nucula bivirgata, Protanisoceras (P.) alternotuberculahim, P. (P.) moreanum (type 

 locality), P. (P.) nodoneum (type locality) and P. (P.) barrense (type locality). 



Approximately 2 kms S. of the centre of Revigny-sur-Ornain, and to the SE. of the 

 N 395, the Societe B.H.T.P. have a large brick and tile works with an extensive 

 clay pit on the SE. side of the Marne-Rhine canal. The pit is worked in two stages by 

 multi-bucket excavators and a sketch section is given in text-fig. 37. Deposition of 

 sediment here was apparently fairly constant and there is an almost perfect transition 

 from the lithology seen at the base to that seen at the top. The only sign of slight 

 condensation occurs approximately 30 feet (9-14 m.) above the base of the section 

 where part-phosphatised and pyritic fossils are more common. 



The fossils are essentially crushed flat, and at the base of the sequence the ammon- 

 ites consist of Hoplites (H.) spp. including H. (H.) dentatus and Metahamites sablieri 

 (d'Orbigny) indicating the spathi Subzone. A higher spathi Subzone fauna ranges 

 up into the top few feet of Division 1, and the band of phosphatised and pyritised 

 fossils about 30 feet (9-14 m.) from the base has yielded ammonites including H. (H.) 

 aff. dorsetensis Spath, H. (H.) pretethydis Spath, and H. (H.) canavariformis com- 

 parable to those found in the upper part of the spathi Subzone in the Weald. 



Anahoplites praecox and A. intermedins appear at the base of Division 2 and range 

 up through the remainder of the measured sequence. In Dr. P. Destombes' collection 

 there is a single example of the sulcate form of A . praecox which indicates the lower 

 part of the intermedins Subzone and was probably derived from the top few feet of 

 Division 1. 



The spathi Subzone is represented in this section, therefore, by about 50 feet 

 (15-24 m.) of sediments, and the base of the Subzone has not yet been reached. The 

 top of the intermedins Subzone has not been reached either, and the exposed portion 

 of sediments belonging to this Subzone is about 15 feet (4-57 m.) thick. 



(b) Pargny-sur-Saulx (Marne) 



In the area of Pargny-sur-Saulx and Maurupt, situated approximately 12 kms SW. 

 of the section at Revigny-sur-Ornain, there is an important centre of brick and tile 

 production. Houdard (1940 ; 625-636) has recorded the distribution of the fauna 

 collected from the Gault (Argiles Tegulines) in this area but there are no details of the 

 sections. From his lists it is apparent that the lyelli and spathi Subzones are definitely 

 present, and probably the intermedins Subzones as at Revigny. His record of 

 ' Acanthoceras ' camatteanum and ' Parahoplites ' steinmanni from Pargny suggested 



