364 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



period of erosion of the Niagara gorge, and are therefore approxi- 

 mately contemporaneous with the Litorina beds of the Baltic. 



In the United States the peat bogs contain plants and animals 

 occurring fossil 50 to 100 miles north of their present limits (142). 

 But here part at least of the warm period fell in a period of submer- 

 gence, for at Boston, "W. Shimer (143) found a fine silt with Mollusca, 

 indicating a warmer climate, 15 feet above mean low tide. In South 

 Carolina also G. T. Pugh (144) concluded from a discussion of the 

 Pleistocene marine Mollusca that there had been a period of sea 

 temperature slightly above the present. 



Isolated pieces of evidence of a warm period immediately pre- 

 ceding the present have been found in many other parts of the globe, 

 e. g., east Africa, east Australia, Terra del Fuego, and Antarctica, 

 but as these have not yet been connected up with the European area 

 I will not describe them further. We have at least evidence of the 

 existence of a series of climatic waves of long period extending over 

 a considerable part of the Northern Hemisphere. 



Before closing this study of the correlation of the Quaternary 

 deposits of northern Europe, there are two points to which I should 

 like to refer; one is the correlation of Penck and Bruckner's Gschnitz 

 and Daun stadia in the light of G. de Geer's "geochronological" work, 

 and the other is the bearing of the loess on the correlation. 



The estimate of postglacial time in the Alps made by Penck and 

 Bruckner chiefly on the basis of the amount of delta formation has 

 already been referred to. This is: 

 Post Wurm period, 20,000 years. 

 Post Bubl period, 16,000 years. 



The "geochronological" work of G. de Geer in Scandinavia is 

 well known; by counting the number of annual layers in lake sedi- 

 ments and identifying certain annual layers from one deposit to 

 another he has been able to calculate the date at which various locali- 

 ties became free from ice, and finds that the receding ice edge reached 

 the south of Scania 12,000 years ago. The recession from the north 

 coast of Germany to the south of Scania can not be calculated in this 

 way, but from a comparison of the amount of melting he estimates 

 about 5,000 years for this period, making a total of 17,000 years 

 since the conclusion of the Baltic oscillation. From these studies 

 there is little doubt that the Baltic oscillation corresponds to the 

 Buhl stadium. 



Further, de Geer gives the age of the great Fennoscandian mo- 

 raines near Stockholm as about 10,000 years. Penck and Bruckner 

 could not obtain a date for the Gschnitz stadium, but for the last of 

 their stadia, the Daun, they calculate a date of about 7,000 years. 

 The Gschnitz stadium, being intermediate, must be something be- 

 tween 9,000 years and 12,000 years in age, so that it is very probable 

 that the Fennoscandian end moraines and the Gschnitz stadium are 



