TABLE OF CONTENTS. 



Page 



Preface "i 



List of Illustrations vin 



The Cahuilla Basin and Desert of the Colorado. By William Phipps Blake 1-12 



Exploration 1 



San Gorgonio Pass 1 



Geologic history 2 



Evidence of uplift 2 



Lake Cahuilla 3 



Desiccation of Lake Cahuilla 5 



Salton Sea 5 



Rate of evaporation 5 



Colorado desert 6 



Fertility of desert soils 7 



Adaptation to agriculture 7 



Geology and minerals 8 



Volcanism 9 



Mud volcanoes 9 



Salt 10 



Asphaltum and petroleum 11 



Sulphur 11 



Sodium carbonate 11 



Gold 11 



Analogous conditions elsewhere 11 



Geographical Features of the Cahuilla Basin. By Godfrey Sykes 13-20 



General description 13 



Early maps and exploration 14 



Modern exploration 15 



The Colorado River and its Delta 16 



The main Delta barrier 16 



The Pattie Basin barrier 17 



The Cahuilla Valley 17 



The Salton Sink 17 



The ancient shore-line 17 



The drainage from the Colorado and Delta 18 



The Whitewater drainage 18 



The Carrizc-San Felipe drainage 18 



The Chuckawalla Wash drainage 19 



Recent history 19 



Sketch of the Geology and Soils of the Cahuilla Basin. By E. E. Free 21-33 



Introduction 21 



Descriptive geology 21 



Historical geology 25 



The soils 29 



Chemical Composition of the Water of Salton Sea and Its Annual Variation in Concentration 



1906-1911. By W. H. Robs 35-46 



Preliminary analysis 35 



Methods of analysis 36 



Silica 36 



Iron and aluminium 36 



Manganese 37 



Calcium and magnesium 37 



v 



