BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 33, pp. 541-5S2 September 1, 1922 



MAP OF THE PLEISTOCENE LAKES OF THE BASIN-AND- 

 RANGE PROVINCE AND ITS SIGNIFICANCE 1 



BY OSCAR E. MEINZER 



(Read before the Society December 29, 1921) 



CONTENTS 



Page 



Introduction 541 



Pleistocene lakes 542 



Present lakes and areas of ground-water discharge 545 



Interpretation of Pleistocene climate 547 



List of Pleistocene lakes in the Basin-and-Range Provinces 550 



Introduction 



The Basin-and-Range physiographic province, as outlined by a com- 

 mittee of the Association of American Geographers and the Physiographic 

 Committee of the U. S. Geological Survey, 2 extends in the United States 

 from southern Oregon to trans-Pecos Texas ; and contains not less than 

 125 closed drainage basins — that is, basins which have no surface outlets 

 for the water that falls upon them. The mountainous rims of these 

 basins, with their great relief and remarkable exposures of geologic for- 

 mations and structures, have, from the beginning of explorations in the 

 region, compelled the attention of geologists. In contrast, the interior 

 depressions of the basins, mantled by recent sediments and with surface 

 features that are hardly discernible except by an experienced observer, 

 have received relatively little attention and are commonly regarded as 

 lacking in geologic interest. However, the serious work that has been 

 done in these interior depressions, or basin valleys, has shown that they 

 contain physiographic and hydrologic features of absorbing interest and 

 much geologic significance, and also sufficient natural and artificial ex- 



1 Manuscript received by the Secretary of the Society February 23, 1922. 

 Submitted by permission of the Director of the U. S. Geological Survey. 



2 N. M. Fenneman : Physiographic divisions of the United States. Annals Assoc. 

 Amer. Geographers, vol. 6, 1916, pp. 19-98. The north boundary of this province was 

 slightly modified for the present paper in order to include Harney Valley, Oregon. 



(541) 



