PROF. G. F. WRIGHT AND HIS CRITICS. 7 6 s 



swept across the field and wiped out the records written as with 

 an iron pen on the rocks, and has engraven in their stead a pal- 

 impsest of its own. The Ice age is now a familiar topic, and its 

 massive ice-sheet a reality to all. The continental glaciers which 

 covered a great part of North America and Europe with ice thou- 

 sands of feet thick, and enduring for thousands of years, literally 

 swept from the face of the country the monuments of preceding 

 life, leaving in their place its own memorials which the geologist 

 is now learning to interpret. 



Here is the unexpected barrier which meets the archaeologist 

 and the geologist in their investigations. They can follow the 

 trail of man back into the Pleistocene era almost or quite to the 

 edge of the ice. There it either becomes exceedingly faint or is 

 lost altogether. In the tangled maze of glacial history the pre- 

 vious confusion is worse confounded, and the thin thread of evi- 

 dence for man's existence is broken or lost. 



The nature and date of the Glacial era and man's relation to it 

 thus become important problems in the main issue, and it is these 

 with which Prof. Wright's book deals. To some geologists the 

 Ice age was single, to others it appears to have been double, triple, 

 or even more complex. Some believe that man was contemporary 

 with the later and even with the earlier stages of the era. Space 

 will not allow us here to do more than mention these divergences 

 of opinion, but so much was necessary in order to understand the 

 scope of the work. 



The appearance of Prof. Wright's little book has been the 

 signal for a renewal of the controversy with fresh energy, not to 

 say with acrimony, yet in it the ordinary reader would scarcely 

 find any cause for commotion. It is for the most part merely a 

 condensation of the same writer's larger work on the Ice Age in 

 North America. Its aim is to lay before the general reader a 

 short sketch of the present state of our knowledge of the Glacial 

 era, and to briefly state the evidence bearing on man's existence 

 during it or any part of it. The book is not sensational ; it con- 

 tains little or nothing that is new ; it publishes no startling facts ; 

 it propounds no novel or strange theories, scientific or unscien- 

 tific ; it is simply, as it professes, a summary view over the field 

 of glacial geology. 



The author is well known to geologists by his share in the 

 epoch-making work of tracing the southern limit of the ice-sheet 

 across the North American continent. This was accomplished 

 by him in connection with Lewis, Upham, Smock, Chamberlin, 

 Cook, Leverett, etc., and, as far as the western Illinois State 

 line, may now be considered definitely known. In this great 

 work Prof. Wright may fairly claim a place among the first, 

 having commenced his studies on the drift hills of Andover, 



