LIST OF ILLUSTRATIONS. 



PLATES. 



Pacs 



1. San Gorgonio Pase. The late Professor W. P. Blake. Saline plain of Salton Sink Facing 2 



2. Map of the Desert of the Colorado 6 



3. Map of the Gulf of California by Castillo 14 



4. Map of the regions about the Gulf by Wytfliet 16 



5. Rocque's map of North America 18 



6. Accretion dune. Crescentic dunes. Old Beach line of Blake Sea. Big Island 22 



7. San Jacinto Mountains. Foothills of Santa Rosa Range 26 



8. Northwest part of Cahuilla Basin. Clay lumps on beach 30 



9. Organisms in brines 62 



10. Cultures of chromogenic bacilli 64 



11. Cultures of chromogenic bacilli 66 



12. Prosopis glandulosa. Dune surrounded by water. Tongues of sea extending up washes 72 



13. Prosopis glandulosa and P. pubescens in various stages of decortication 74 



14. Decortication of Larrea tridentata ; Culture of Beggiatoa 76 



15. Map of Salton Sink 116 



16. Emersion of 1907, Imperial Junction Beach. Big Island and Rock Island, from Obsidian Island 120 



17. Travertine Wash, February 1907. Travertine Wash, February 1909 124 



18. Upper limit of Travertine Terraces, February 1908. Strand of 1907, Travertine Terrace, November 1908 126 



19. Travertine Wash, November 1909. Channels of desert washes after submergence 130 



20. Emersion of 1907, Imperial Junction Beach, October 1911. Emersion of 1907, Travertine Terraces, 



October 1911 132 



21. Southeast point of Obsidian Island, October 1912. Strand of East Bay, Obsidian Island, October 1912 134 



22. Strand of 1909, Travertine Terraces, October 1912. Ranch on emersion of 1910, Mecca, October 1912 136 



23. Emersion of 1910, Mecca, October 1912. Emersion of 1911, Mecca, October 1912 138 



24. Uppermost portion of strand of 1911, Travertine Terraces, October 1912. Strand of 1911, Imperial 



Junction Beach, October 1912 138 



25. Travertine Wash, October 1912. Cut bank of mid-winter 1911-12, Travertine Terraces 140 



26. Cut bank at upper limit of strand of 1913. Cut bank of 1913, three months later 142 



27. Flotation of seedlings of Atriplex lentiformis 146 



28. Strands of 1909 and 1910, Imperial Junction Beach, October 1911. Dead stems bearing fruits and seeds 



on submerged areas. Rank of Suseda on strand near Saltan station 152 



29. Prosopis and Cucurbita on strand of 1907, Obsidian Island. Rank of vegetation on ancient strands; high 



beach-line of Blake Sea 164 



30. Ranks of ancient vegetation of Blake Sea. Heliotropium as pioneer on emersed island 168 



31. Pluchea and Spirostachys as pioneers on islands. Baccharis as pioneer on Cormorant Island 170 



32. Islands and bars, southwest shore of Salton Sea. Spirostachys near cormorant's nest on new island 170 



FIGURES IN TEXT. 



1. Detail of Rocque's map showing body of water separated from head of Gulf of California 16 



2. Diagram showing fluctuations of water and organisms in brine 61 



3. Curves showing alterations in level of Salton Sea, 1905-12, with estimated inflow 138 



4. Diagram showing recession of sea at Travertine Terraces, 1907-12 138 



IX 



