AGE OF HUMAN RACE — RICHAIIZ 453 



uiiearllied. Man uf the Xcanderthul luce, livin«j; in the lirst portion 

 of the Old 8tone A«^e, in the cultural sta<^es of the Aehculian and 

 Mousterian, is reinesented at least by li skeletons, of wliich 7 are in 

 good preservation, au«.l by fra^niental remains of ly individuals. 

 Neanderthal man was sucx.'eeded by quite a dilierent human race which 

 lived in the last part of the Old Stone A^e antl the glacial period. 

 Fifty-two skeletons of this race are extant and })ortions of otlier 

 skeletons representing about 30 individuals. 



AN ABSOLUTE CHRONOLOGY FOR LATE GLACIAL AND POSTGLACIAL 



TIME 



Are there reliable methods for dating back these geologic events 

 and for expressing in millenniums the time elapsed since their occur- 

 rence!^ Many attempts have been made in the past to determine this 

 time. Most of them did not go beyond rough estimates, leaving mucli 

 to subjective feeling and fancy. Tlie cutting of the Niagaia gorge 

 below the falls is supposed to furnish a good measure of the time 

 elapsed since the recession of the ice, for these falls could not begin 

 their work before the ice sheet covering North America beyond New 

 York City retreated to a place north of the present falls. But there 

 are so many uncertainties in the determination of this time that the 

 figures given differ all the way from 7,00U to uy,UUO years. Besides, 

 the connection of this event with the appearance of man in Europe 

 is still very problematical. Even more open to exception are calcula- 

 tions based on the thickness of deposits left in lakes after the 

 recession of the ice. 



The study of such deposits in lakes, however, was developed bv 

 Prof. Gerard Baron de Gcer, of Stockholm, into a new method 

 which is recognized as the best and most reliable one for measuring 

 the millenniums since the definite recession of the ice from a given 

 locality. Professor de Geer reported on this method and its results 

 to the Eleventh International Geologic Congress sitting in Stock- 

 holm in 1910.' Since then it has been applied to numerous localities 

 both in Europe and in America by De Geer and his students and co- 

 workers, and it has found unreserved approval and acceptance f lom 

 geologists. 



To illustrate De Geer's procedure we may take an example of a 

 recent glacier. The molting waters of the Victoria Glacier in the 

 Canadian Kockies (Alberta), after a course of about 1 mile, are 

 poured into l^ake Louise, a mountain lake li/i miles long and one-half 

 to three-eighths mile wide and 5,700 feet above sea level. During the 

 summer months the melting waters of the glacier are turbid and milky 

 from the detritus carried away from the melting ice. In the lake 



'A geochronology of the last 12,000 years, Congr&s gi-ol. Intern, xi. Porapli' rt'ndci, 

 Stockholm, 1912, p. 241 st. 



1^8095—31 ;^0 



