DEPARTMENT OF BOTANICAL RESEARCH. 61 



arrangement of the masses of travertine led to the conclusion that 

 their origin may be traced to the action of a complex of bacteria and 

 algae after the manner of the deposits which are now being formed in 

 the Salton Sea, which have been studied by Professor Brannon (see 

 Annual Report of this Department for 1912). The current theories 

 of Quaternary lakes have been based largely upon a purely chemical 

 interpretation of the tufa deposits. The estabhshment of the fact 

 that organic agencies have participated will render necessary some 

 revision of ideas concerning the course of existence of such bodies of 

 water as Lake Lahontan. Professor Jones has already carried his 

 work to the lakes representing the remains of this ancient pea and 

 concludes, for example, that Pyramid Lake has not been desiccated 

 since Lahontan was first formed, and that it has taken about 2.000 

 years to accumulate the salt contained in the present lakes. The 

 continuation of the work will involve a comparison of features in the 

 basin in which Blake Sea formerly occupied the Salton Sink and of 

 the basin in which Lake Lahontan formerly lay. 



Seventh Annual Analysis of the Salton Sea Water, by A. E. Vinson. 



During 373 days (from June 10, 1912, to June 18, 1913) the total 

 solids in Salton Sea water have increased from 846.55 parts to 

 1,002.56 parts per 100,000, an increase of 18.4 per cent for the period. 

 When calculated for the year ending June 3, 1913, by the method 

 suggested in the Twenty-second Annual Report, Arizona Agricul- 

 tural Experiment Station, the annual increase becomes 17.7 per cent 

 (17.5 for the year ending June 3, 1912). The Salton water may now 

 be considered as 1 per cent brine. 



Parts in ParU in 



100,000 100,000 



Total solids (dried at 110° C.) plus water of Lithium, Li 



occlusion and hydration 1,002 . 56 Chlorine, CI 473 . 89 



Water of occlusion and hydration 32 . 6 Sulphuric, S0< 124 . 65 



Sodium, Na ;. 323.08 Carbonic, CO3 in total solids 



Potassium, K 3.45 Carbonic, COj total 11.28 



Calcium, Ca 19.75 Bicarbonic, HCOs volumetric 15.94 



Magnesium, Mg 16.22 Silicic, SiOi 2. 18 



Aluminum, Al 1.25 Phosphoric, P0« Trace. 



Iron, Fe 0.38 Nitric, NO3 None. 



Manganese, Mn None. Nitrous, NO2 None. 



Zinc, Zn None. Oxygen consumed 0.110 



Lead, Pb None. Boric acid Trace. 



Copper, Cu 



Calcium, again, shows a marked decrease, having concentrated 

 only 14.5 per cent, and some additional calcium undoubtedly was 

 brought into the sink by drainage. The total carbon dioxide and 

 also the bicarbonic radicle show a less concentration than last year. 



