Part IV.] CAINOZOIC OR TERTIARY, 835 
PART IV.—Carnozoic or Terriary. 
The close of the Mesozoic periods was marked in the west of - 
Europe by great geographical changes, during which the floor of 
the Cretaceous sea was raised partly into land and partly into 
shallow marine and estuarine waters. These events must have occu- 
pied a vast period, so that when sedimentation once more became 
continuous in the region, the organic remains of Mesozoic time had 
(save in a few low forms of life) entirely disappeared and given 
place to others of a distinctly more modern type. In England, the 
interval between the Cretaceous and the next geological period 
represented there by sedimentary formations is marked by the abrupt 
line which separates the top of the Chalk from all later accumu- 
lations, and by the evidence that the Chalk seems to have been in 
some places extensively denuded before even the oldest of what are 
called the Tertiary beds were deposited upon its surface. There is 
evidently here a considerable gap in the geological record. We have 
no data for ascertaining what was the general march of events in 
the south of England between the eras chronicled respectively by 
the Upper Chalk and the overlying Thanet beds. So marked is this 
hiatus that the belief was long prevalent that between the records of 
Mesozoic and Cainozoic time there comes one of the great breaks in 
the geological history of the globe. 
Here and there, however, -in the continental part of the Anglo- 
Parisian basin traces of some of the missing evidence are obtainable. 
Thus, the Maestricht (Danian, p. 827) shelly and polyzoan lime- 
stones, with a conglomeratic base, contain a mingling of true Creta- 
ceous organisms with others whick are characteristic of the older 
Lertiary formations. The common Upper Chalk crinoid, Bour- 
gueticrinus eliipticus, occurs there in great numbers; also Ostrea 
vesicularis, Baculites Fawasit, Belemnitella mucronata, and the great 
reptile Mosasaurus; but associated with such Tertiary genera as 
Voluta, Fasciolaria, and others. At Faxoe, on the Danish island 
of Seeland, the uppermost member of the Cretaceous series contains 
in like manner a blending of well-known Upper Chalk organisms 
with the Tertiary genera Cyprea, Oliva, and Mitra, In the neigh- 
bourhood of Paris also, and in scattered patches over the north of 
France, the Pisolitic limestone, formerly classed as Tertiary, has been 
found to include so many distinctively Upper Cretaceous forms as 
1o lead to it being relegated to the top of the Cretaceous series, 
from which, howeyer, it is marked off by the decided unconform- 
ability already described. These fragmentary deposits are In- 
teresting, in so far as they help to show that, though in western 
Europe there is a tolerably abrupt separation between Cretaceous 
and ‘l'ertiary deposits, there was nevertheless no real break Pa 
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