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services of Dr. Ernst Antevs, formerly of the University of 
Stockholm, who has prepared the following brief f popular outline 
of the geology of that period. 
Dr. Antevs was a pupil of Baron De Geer, a student of glacial 
chronology and founder of the Stockholm Geochronological In- 
stitute. Baron De Geer discovered the possibility of using the 
very fine layers or varves of clay deposited during the melting of 
the Quaternary ice sheet as a geological clock or time-piece. The 
method is described in the following pages. Dr. Antevs coop- 
erarted with Baron De Geer in working out the time scale in Swe- 
den, and in 1920 he came to America to study varves in this 
country for the purpose of 
— 
correlating American glaciation in 
time with that of Sweden. During this work he has traced 
series of clay layers in the Connecticut Valley which record 
period of approximately 4000 successive years, and has been able 
to chart the successive positions of the frontal edge of the ice as 
it melted back (* retreated”), and to assign to each position its 
relative date. THe has extended these studies to the Hudson Bay 
region in Canada. 
From the botanical point of view it is interesting to note that 
the data based on a study of the annual “rings” or layers of 
growth in the trunks of the Giant Sequoia trees of California, the 
oldest known living objects, probably will afford a possibility to 
extend the Swedish late-glacial, postglacial, and recent varve chro- 
nologies up to the present time. On the other hand there is no 
prospect of correlation between American clay records and the 
growth curves of the Big Trees, for these latter extend back only 
3200 years, while the youngest varves measured in Canada are 
some 10,000 years old. The Sequoia studies have been made by 
Dr. A. EX. Douglass, of the University of Arizona, at Tucson, 
Dr. Ellsworth Huntington, of Yale University, Dr. Antevs, and 
others,” 
pa 
"On December 18, 1931, Dr. Antevs and Dr. Douglass each received the 
Research Corporation prize of $2500 and plaque for their scientific contribu- 
tions to the chronology of the pre-historic and geological past, the two meth- 
ods above mentioned being considered as the most original and most exact 
yet devised. 
