ia 
‘Parr IL Seer. iii. § 2] CRETACEOUS. 897 

and consisting of marly chalk with Inoceramus labiatus, I. Brongniarti, 
Ammomtes nodosoides, A. peramplus, Terebratulina gracilis. He places the 
zone of Holaster planus at the base of the Senonian groups, and believes 
that in the hiatus between it and the Turonian beds below the greater 
part of the Turonian series is really wanting in the north. On the other 
hand, Dr. Barrois and others would rather regard the zone of Holaster 
planus as the top of the Turonian series. In the north of France, as 
in England, it is a division of the White Chalk, containing Ammonites 
peramplus, Scaphites Geinitzii, Spondylus spinosus, Inoceramus ineequivalvis, 
Terebratula semiglobosa, Holaster planus, Ventriculites moniliferus, &c. Strata 
with Inoceramus labiatus, marking the base of the Turonian groups, can 
be traced through the south and south-east of France into Switzerland. 
These are overlaid by marls, sandstones, and massive limestones with 
Hxogyra (Ostrea) columba and enormous numbers of hippurites (Hippurites 
cornuvaceinim, Radiolites cornupastoris, &c.). ‘These hippurite limestones 
sweep across the centre of Hurope and along both sides of the great 
Mediterranean basin into Asia, forming one of the most distinctive 
landmarks for the Cretaceous system. 
Senonian.—This formation is most fully developed in the northern 
basin, where it consists mainly of white chalk separable into the two 
divisions of, Ist, Micraster group, composed of chalk beds, in the lower of 
which Micraster cor-testudinaritum and in the upper M. cor-anguinum is the 
prevalent urchin. The same paleontological facies occurs in this and the 
other group as in the corresponding strata of England already described. 
2nd. Belemnitella group with B. quadrata in a lower zone, and B. mucro- 
nata (Meudon chalk) in a higher. In the south and south-east of France 
the corresponding beds are partly marine, partly fresh-water, and contain 
beds of lignite. | 
Danian.—This subdivision of the Cretaceous system appears to be 
developed only in the northern basin. In the neighbourhood of Paris 
and in the Departments of Oise and Marne a rock long known as the 
Pisolitic Limestone occurs in patches, lying unconformably on the White 
Chalk. The long interval which must have elapsed between the highest 
Senonian beds and this limestone is indicated not only by the evidence 
of great erosion of the chalk previous to the deposit of the limestone, 
but also by the marked paleontological break between the two rocks. 
The general aspect of the fossils resembles that of the older Tertiary for- 
mations, but among them are some undoubted Cretaceous species. In 
the south-east of Belgium the Danian series is well exposed, resting un- 
conformably on a denuded surface of chalk. In Hainault it consists of 
successive bands of yellowish or greyish chalk, between some of which 
there are surfaces of denudation, with perforations of boring molluscs, so 
that it contains the records of a prolonged period (chalk of St. Vaast, 
Obourg, Nouvelles, Spienne, and Ciply). Among the fossils are Belem- 
nitella mucronata, Baculites Faujasii, Nautilus Dekayi (but no Ammonites, 
- Hamites, or Turrilites), Inoceramus Cuvieri, Ostrea flabelliformis, O. lateralis, 
O. vesicularis, Crania ignabergensis, Terebratulina striata, Fissurirostra Palissii 
(characteristic), Radiolites ciplyanus, Eschara several species and in great 
numbers, Ananchytes ovatus, Holaster granulosus. 'The well-known chalk 
of Maestricht is equivalent to part of these strata, but appears to 
embrace also a higher horizon containing Hemipneustes striato-radiatus, 
Crania ignabergensis, Terebratulina striata, Fissurirostra pectiniformis, Ostrea 
