206 CHRONOLOGICAL RELATIONS CHAP. x:i. 



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. 



THEEQUENT allusions have been made in the preceding 

 J- pages to a period called the glacial, to which no refe 

 rence 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 e boulder 

 clay ' or * northern drift.' This formation is usually quite 

 destitute of organic remains, so that the thread of our in 

 quiry into the history of the animate creation, as well as of 

 man, is abruptly cut short. The interruption, however, is by 



