2 6o THE POPULAR SCIENCE MONTHLY. 



since been found at three of the places which he specifically- 

 pointed out. 



During the summers of 1884 and 1885 he was employed with 

 the United States Geological Survey in tracing the glacial bound- 

 ary across Illinois, and in reviewing the field in Ohio and west- 

 ern Pennsylvania. His report of this work appeared in 1890, as 

 Bulletin 58 of the United States Geological Survey, on The Gla- 

 cial Boundary in Western Pennsylvania, Ohio, Kentucky, Indiana, 

 and Illinois. In the summer of 18S6 he visited Washington Ter- 

 ritory and examined the Muir Glacier in Alaska, where he spent 

 the month of August in company with the Rev. J. L. Patton and 

 Mr. Prentiss Baldwin, collecting facts concerning the motion, 

 size, present general condition, and probable past history and 

 future career of the glacier. He devoted the two following sea- 

 sons to the further exploration of Ohio and of Dakota, and other 

 parts of the Northwest. " Thus/' he says, " I have personally been 

 over a large part of the field containing the wonderful array of 

 facts " which he presents in his Ice Age in North America. 



Since making these systematic explorations, while he has con- 

 tinued his outdoor work in various fields, Prof. Wright has de- 

 voted much attention to presenting the results of his researches 

 to the public. He delivered courses of lectures on the subject 

 before the Lowell Institute in Boston in the fall of 1887, before 

 the Peabody Institute in Baltimore in 1888, and in Brooklyn, 

 N. Y. The substance of these lectures, rewritten and much added 

 to, was published in 1889 in his noble book, the Ice Age in North 

 America and its Bearings on the Antiquity of Man, a large illus- 

 trated volume of 648 pages, which may be fitly described as one 

 of the most valuable of recent contributions to the literature of 

 geology, and as marking an important step in the advance of the 

 science. The volume also contains an exhaustive discussion of 

 the evidences concerning the early presence of man on the Ameri- 

 can continent, and particularly his existence during the ice age. Be- 

 sides incorporating in this discussion the fruits of the discoveries of 

 Dr. Metz in Ohio, of Cresson at Medora, Ind., and Claymont, Del., 

 of Winchell and Miss Babbitt in Minnesota, of Dr. Abbott in the 

 Delaware Valley, of Whitney in California, etc., he has intro- 

 duced discoveries in regard to which he has himself made careful 

 investigations ; of the paleolithic implements found at Newcomers- 

 town, Ohio, of the image found at Nampa, Idaho, under the basalt, 

 and of a stone mortar found under Table Mountain in California. 

 As a professor habituated to theological studies, the question of 

 man's antiquity naturally followed him in these investigations, 

 with the inevitable conclusion that the human period must be 

 allowed an extension far beyond previous ideas of the subject, as 

 well as the question of the method of reconciling the fact with 



