CHAPTER XII.
ANTIQUITY OF MAN RELATIVELY TO THE GLACIAL PERIOD AND TO THE EXISTING FAUNA AND FLORA.
CHRONOLOGICAL RELATION OF THE GLACIAL PERIOD, AND THE EARLIEST KNOWN SIGNS OF MAN'S APPEARANCE IN EUROPE—SERIES OF TERTIARY DEPOSITS IN NORFOLK AND SUFFOLK IMMEDIATELY ANTECEDENT TO THE GLACIAL PERIOD—GRADUAL REFRIGERATION OF CLIMATE PROVED BY THE MARINE SHELLS OF SUCCESSIVE GROUPS—MARINE NEWER PLIOCENE SHELLS OF NORTHERN CHARACTER, NEAR WOODBRIDGE—SECTION OF THE NORFOLK CLIFFS—NORWICH CRAG FOREST BED AND FLUVIO-MARINE STRATA—FOSSIL PLANTS AND MAMMALIA OF THE SAME—OVERLYING BOULDER CLAY AND CONTORTED DRIFT—NEWER FRESHWATER FORMATION OF MUNDESLEY COMPARED TO THAT OF HOXNE—GREAT OSCILLATIONS OF LEVEL IMPLIED BY THE SERIES OF STRATA IN THE NORFOLK CLIFFS—EARLIEST KNOWN DATE OF MAN LONG SUBSEQUENT TO THE EXISTING FAUNA AND FLORA.
FREQUENT allusions have been made in the preceding pages to a period called the glacial, to which no reference is made in the Chronological Table of Formations given at p. 7. It comprises a long series of ages, chiefly of post-tertiary date, during which the power of cold, whether exerted by glaciers on the land, or by floating ice on the sea, was greater in the northern hemisphere, and extended to more southern latitudes than now.
It often happens that when in any given region we have pushed back our geological investigations as far as we can, in search of evidence of the first appearance of man in Europe, we are stopped by arriving at what is called the 'boulder clay' or 'northern drift.' This formation is usually quite destitute of organic remains, so that the thread of our inquiry into the history of the animate creation, as well as of man, is abruptly cut short. The interruption, however, is by
