PREFACE. 



No subject of Geological investigation is perhaps in a 

 more unsatisfactory state than that which relates to 

 the connection of the modern or human period with 

 preceding epochs. Difficult and complex problems, 

 yet unsolved, and even imperfectly understood in 

 their data and conditions, encompass the history of 

 that remarkable Glacial Age which seems to have 

 preceded the advent of man and the modern mammalia 

 in the Northern Hemisphere. Much uncertainty and 

 liability to error attach to the study of the superficia 1 

 deposits which alone contain the remains of man and 

 his works. Further, the Geologist, the ArchaBologist, 

 and the Historian, the Philologist and the Anthropo- 

 logist, approaching this obscure region from different 

 directions, all claim to be heard, and often vie with 

 each other in dogmatic assertions respecting facts and 

 inferences of the most uncertain character. 



The present work is intended as a popular exposi- 

 tion of some of the more important topics, from the 



