360 Diller — Klamath Mountain Section, California. 



from whose eruptions there is a great mass of tuff in the 

 Sacramento Valley cropping out all along its western border 

 from Gas Point to Thomas Creek. Lassen Peak is the nearest 

 large volcano, and its known tuffs are separated from those of 

 the basins referred to above by about 20 miles over a low 

 mountain. With a view to determine certainly if possible the 

 source of the material of the tuff, two chemical analyses were 

 made by Dr. E. T. Allen. One specimen was from Rice's 

 quarry, six miles southeast of Paskenta, representing the tuff 

 of the Sacramento Valley ; the other specimen is from the 

 Pedding Creek basin. 



Analyses of Lassen Peak Lavas and Tuffs. 





1 



2 



3 



4 



5 



6 



7 



8 



SiO 



58-08 



68-72 



76-75 



70-01 



65-78 



67-27 



60*23 



70-40 



A1 2 3 



18-37 



15-15 



12-32 



12-61 



14-87 



14-84 



18-64 



13-50 



Fe 2 3 



2-92 



1-16 





1-47 



1-27 



1-01 



3-81 



1-3L 



FeO 



3-38 



1-76 



1-36 



•50 



1- 



•85 



•88 



1-61 



MgO 



3-35 



1-28 



none 



•72 



1-89 



1-36 



1-64 



•37 



CaO 



7*05 



3-30 



1-18 



1-06 



2-41 



2-30 



6-04 



•56 



Na 9 



3-66 



4-26 



3-55 



1-94 



2-58 



2-94 



3-87 



2-11 



K 2 



1-33 



2-78 



3-98 



5-12 



2-71 



2-87 



1-46 



2-39 



H 2 0- 



1-09 



•74 



•54 



2-37 



2-87 



1-55 



•95 



1-C5 



H 2 + 







__. 







4-68 



432 



4-95 



1-97 



7-41 



TiO a 



•44 



•31 













•27 



•57 







ZrO a 



- . _ 















none 



•01 



_ _ . 



co 2 













... 







none 



none 





PA 



•16 



•09 







•04 



•08 



•06 



•20 



•08 



CI 

 F 



s 

 OA 







— 





— 



— 



none 



none 





none 



none 



.... 



... 



--- 



trace 



trace 



... 



NiO 

















_ - - 











MnO 



•13 



0-11 







trace 



trace 



trace 



trace 



trace 



BaO 



•03 



•07 















•15 



•11 



_ . _ 



SrO 



•02 



•03 















none 



•05 







Li 2 



trace 



trace 



... 



... 



--- 



--- 



... 



... 



100-01 99-76 9968 100*52 99*78 100'38 100*43 100*79 



1. Andesite. Old rim of Lassen Peak. Analyst, W. F. Hille- 



brand. 1887. 



2. Dacite of last eruption at northwest base of Lassen Peak. 



Analyst, W. F. Hillebrand. 1887. 



3. Glass base from dacite of Lassen Peak. Analyst, P. W. 



Shimer. 1883. 



4. Tuff about 40 miles southeast of Lassen Peak. Analyst, 



George Steiger. 1893. 



