CHAP. XII.

THE GLACIAL AND HUMAN PERIODS,

245

PART II.

THE GLACIAL PERIOD CONSIDERED WITH REFERENCETO THE ANTIQUITY OF MAN

CHAPTER XIL

ANTIQUITY OF MAN RELATIVELY TO THE GLACIAL PERIOD AND TOTHE EXISTING FAUNA AND FLORA.

CHRONOLOGICAL RELATION OF THE GLACIAL PERIOD, AND THE EARLIESTKNOWN SIGNS OF MAN’S APPEARANCE IN EUROPE —SERIES OF TERTIARYDEPOSITS IN NORFOLK AND SUFFOLK IMMEDIATELY ANTECEDENT TOTHE GLACIAL PERIOD — GRADUAL REFRIGERATION OF CLIMATE PROVED

BY THE MARINE SHELLS OF SUCCESSIVE DEPOSITS-FOREST BED OF

CROMER AND FLUVIO-MARINE STRATA—FOSSIL PLANTS AND MAMMALIAOF THE SAME—TABLE OF THE SUCCESSION OF BEDS ON THE NORFOLKCOAST—ARCTIC PLANTS IN THE LIGNITE LAYERS OVERLYING THEFOREST BED—OVERLYING CONTORTED DRIFT, MID-GLACIAL SANDS, ANDBOULDER CLAY-—NEWER FRESHWATER FORMATION OF MUNDESLEYCOMPARED TO THAT OF HOXNE — GREAT OSCILLATIONS OF LEVEL IM-PLIED BY THE SERIES OF STRATA IN THE NORFOLK CLIFFS—EARLIESTKNOWN DATE OF MAN LONG SUBSEQUENT TO THE APPEARANCE OF THEEXISTING FAUNA AND FLORA.

1 AREQUENT allusions have been made in the preceding- pages to a period called the glacial, to which no refer*ence is made in the Chronological Table of Formations givenat p. 5. It comprises a long series of ages, chiefly of post-tertiary date, during which the power of cold, whether exertedby glaciers on the land, or by floating ice on the sea, was-greater in the northern hemisphere, and extended to moresouthern latitudes than now.