Arkell.1956.Jurassic..

THE BOULONNAIS 43
de Lor., P. chloroolithicus (Gumbel), P. cotovui Sim., Cardioceras densiplicatum
Boden, C. cf. tenuiserratum (Oppel) (Arkell, 1948, p. 389).
(>'5 4
Marne a Millericrinus of La Liegette railway-cutting; Cardioceras
cordatum is recorded, but the ammonites of this bed have yet to be
reinvestigated. (5 m.).
Argile du Coquillot, upper part. Abundant small pyritized ammonites
of the Mariae Zone, including Q. mariae and its allies, Scarburgiceras
scarburgense and Creniceras renggeri (listed Arkell, 1939, pp. 208-9).
(6-10 m.).
CALLOVIAN (115 m.)
Argile du Coquillot, lower part, with pyritised Quenstedtoceras lamberti
(Sow.) and its allies, Distichoceras bicostatum (Stahl) and a 30 cm. band of
marly limestone (2 m.).
Argile de Montaubert, worked for bricks near le Wast, with Kosmoceras
spp. recorded as K. duncani and K. jason, and Erymnoceras coronatum
(6-25 m.).
Marne ferrugineuse de Belle, from which Sigaloceras calloviense is
recorded (0-6 m.). At base derived Cornbrash fossils.
Calcaire des Pichottes, upper part: Upper Cornbrash with Macrocephalites
herveyi (Sow.), M. typicus Blake, M. tumidus auct. (Dutertre,
1926, p. 48) (1-2 m.).
BATHONIAN (26 m.)
Calcaire des Pichottes, lower part: Lower Cornbrash with Clydoniceras
discus (Sow.), Delecticeras legayi (Rig. & Sauv.), Choffatia cf. subbakeriae
(d'Orb.) and Cererithyris intermedia (Sow.) (Dutertre, 1928, p. 59)
(0-33-2 m.).
Calcaire marneux a Rhynchonella elegantula. A large Clydoniceras cf.
discus (Sow.) recorded (Dutertre, 1926, p. 48) (3 m.).
Oolithe de Marquise, with Rhynchonella hopkinsi (8 m.).
Calcaire oolitique de Rinxent, with abundant Rh. concinna and obscure
Perisphinctids compared to Siemiradzkia and Procerites (Dutertre, 1926,
p. 48) (12-13 m.).
Sables d'Hydrequent, without ammonites (1-3 m.).
[CARBONIFEROUS LIMESTONE below, containing solution pipes filled with
sands and clays with Rhaetic plants and shells of large Unionids
(Corsin, 1951).]
PAYS DE BRAY
About midway between the Boulonnais and Normandy a small inlier
of Kimeridgian and Portlandian rocks is brought to the surface in the
core of the Pays de Bray pericline. The lowest beds exposed are in the
Pseudomutabilis Zone, consisting of clays and lumachelles of Exogyra
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