BRIDLINGTON DRIFT. 
189 
TERTIARY OR CAINOZOIC PERIOD. 
CHAPTER XIII. 
PLIOCENE PEKIOD. 
Glacial Formations of Pliocene Age.—Bridlington Beds.—Glacial Drifts of 
Ireland.—Drift of Norfolk Cliffs.—Cromer Forest-bed.—Aldeby and Chil- 
lesford Beds.—Norwich Crag.—Older Pliocene Strata.—Red Crag of Suf¬ 
folk.—Coprolitic Bed of Red Crag.—^White or Coralline Crag.—Relative 
Age, Origin, and Climate of the Crag Deposits.—Antwerp Crag.—Newer 
Pliocene Strata of Sicily.—Newer Pliocene Strata of the Upper Yal d’Ar- 
no.—Older Pliocene of Italy.—Subapennine Strata.—Older Pliocene Flora 
of Italy. 
It will be seen in the description given in the last chapter 
of the Post-pliocene formations of the British Isles that they 
comprise a large proportion of those commonly termed gla¬ 
cial, characterized by shells which, although referable to liv¬ 
ing species, usually indicate a colder climate than that now 
belonging to the latitudes where they occur fossil. But in 
parts of England, more especially in Yorkshire, Norfolk, and 
Suffolk, there are superficial formations of clay with glaci¬ 
ated boulders, and of sand and pebbles, containing occasion¬ 
al, though rare, patches of shells, in which the marine fauna 
begins to depart from that now inhabiting the neighboring 
sea, and comprises some species of mollusca not yet known 
as living, as well as extinct varieties of others, entitling us 
to class them as Newer Pliocene, although belonging to the 
close of that period and chronologically on the verge of the 
later or Post-pliocene epoch. 
Bridlington Drift. — To this era belongs the well-known 
locality of Bridlington, near the mouth of the Humber, in 
Yorkshire, where about seventy species or well-marked vari¬ 
eties of shells have been found on the coast, near the sea-lev¬ 
el, in a bed of sand several feet thick resting on glacial clay 
with much chalk debris, and covered by a deposit of purple 
clay with glaciated boulders. More than a third of the spe¬ 
cies in this drift are now inhabitants of arctic regions, none 
of them extending southward to the British seas; which is 
the more remarkable as Bridlington is situated in lat. 54° 
