X LIST OF PLATES. 



PX.ATE XIX. Eidge of Archaean Qaartzite, East Humboldt Eange, 



Nevada facing page 540 



XX. Sou Springs, Osobb Valley, Nevada do 704 



( Hot Spring Tufa Cone, Provo Valley, Utah. ) 

 ( Hot Spring Tufa, Osobb Valley, Nevada ... ) 



do.... 712 



XXII. Soda Lake, Carson Desert, Nevada . do 746 



XXIII. Columnar Ehyolite, Karnak, Nevada do ... . 702 



XXIV. Pliocene Bluffs, Truckee Eiver, below Wads worth, Nevada, do 818 



XXV. Pyramid and Tufa Domes, Pyramid Lake, Nevada do 824 



