MAN AND THE LAVA BEDS. 709 



arctic butterflies and the Alpine flowers upon the summit of 

 Mount Washington, as well as the gigantic forests of Califor- 

 nia and some of their more distant relatives on the Atlantic 

 coast, were fugitives from the arctic regions in glacial times, 

 who have since become naturalized citizens of the lower lati- 

 tudes. And, Anally, man himself is connected with the clos- 

 ing centuries of the Glacial period in the United States. 

 American scholars who are ambitious to carry on archaeo- 

 logical investigations need no longer go to the valley of the 

 Euphrates or the Nile, or to the languages of central Asia, 

 to find the oldest relics of man in the world, or the surest 

 means of determining the greatness of his antiquity. A 

 boundless, comparatively unworked, most promising and most 

 interesting field lies before the American investigator in the 

 glacial problems of his own country. Nowhere else in the 

 world did the ice of the Glacial period deploy out upon so 

 wide a margin of dry land, and leave so inviting and easy a 

 field of study. Every river rising within the glacial boundary 

 and emerging from the glaciated region presents a problem 

 worthy of the life-long attention of any investigator. Every 

 glacial waterfall and every glacial lake holds out the possibil- 

 ity of yielding up an important clew to chronological ques- 

 tions of absorbing interest. The ingenuity of Professor Asa 

 Gray and others in tracing out the effects of the great Ice 

 age upon the distribution of plants and animals, has only 

 introduced us to subjects which need yet to be worked out 

 in endless detail. The object of the present treatise will be 

 largely accomplished if it serves to stimulate and guide the 

 host of local investigators which the subject is sure to in- 

 terest. 



