S52 B. HUNTINGTON GLACIAL PERIOD IN NON-GLACIATED REGIONS 



Page 

 Pleistocene (and Pliocene) deposits of Turfan 37G 



1. Lacustrine layers 370 



2. Vegetal layers 37G 



Comparison of the Pleistocene vegetal layers of Turfan with Mesozoic 



coal beds 378 



Characteristics and origin of red strata 379 



1. Features indicating subaerial origin 379 



2. Features indicating origin under arid conditions 380 



Summary of conclusions as to the Pleistocene climatic strophe 382 



Comparison of the Pleistocene and Permian strophes 384 



Possible climatic significance of the red and white Moencopie shales of 



Utah 384 



Introduction 



In the progress of geology the influence of climate has been one of the 

 last great subjects to receive attention. During a residence of four years 

 in the dry eastern part of Asiatic Turkey, from 1897 to 1901, the im- 

 portance of climatic influences was impressed on me by the contrast 

 between the topography and superficial deposits of that semi-arid region 

 and those of the moister, glaciated portion of the United States. The 

 impression was strengthened in 1902, when, as a member of a party 

 under the leadership of Professor Davis, of Harvard University, I visited 

 the arid region of Utah and Arizona. There, not only do the superficial 

 deposits and topography bear the impress of prolonged aridity, but the 

 wonderful cross-bedding of the white Colob sandstone and the red color 

 of the underlying Ivanab formation apparently point to the existence of 

 still more arid conditions during the Mesozoic era. 



In the spring of 1903, as assistant once more to Professor Davis, I 

 accompanied the Pumpelly expedition of the Carnegie Institution of 

 Washington to Eussian Turkestan. Thence I made journeys to Kash- 

 gar, in Chinese Turkestan, in the summer of 1903, and to Seyistan (Sis- 

 tan or Seistan), in eastern Persia, early in 1904. In these countries, as 

 is set forth in "Explorations in Turkestan," still stronger evidences of 

 the geologic importance of climate present themselves. The next year, 

 1905, brought an opportunity for a journey of fifteen months' duration 

 in northern India, Chinese Turkestan, and Siberia, as a member of Mr 

 Eobert L. Barrett's expedition to Central Asia. In Chinese Turkestan 

 I traversed what is probably the most unmitigated desert in the world, 

 the great salt plain of Lop. Since the completion of this last journey, 

 the liberal terms of a Hooper Fellowship, held as a non-resident member 

 of the Graduate School of Arts and Sciences of Harvard University, have 



