REPORT OF ASSISTANT SECRETARY. ISl 



(l!) Slaggy aud glassy lava, from the IIinA-aiian Islands and tlic Yel- 

 lowstone National Taik. 



(3) Puniict'ous aud glassy lavas (obsidians), from the Yellowstone 

 National Tark aud the Mono craters, California; vesicular lava, from 

 near Flagstaff, Ariz. 



(4) Lava showing the aa, palioehoe, and other structures dependent 

 upon their varying degrees of viscosity; lava stalactites and driblet 

 cones from the Hawaiian Islands. 



(5) Volcanic bombs, from Lipari, Etna, the extinct volcanoes of Mount 

 Trumbull and Sunset Peak, Arizona; lapilli, from Ice Springs Buttes, 

 in Utah, and Sunset Teak, Arizona. 



(6) Sand, rock fragments, ash, etc., from Bogoslof Island. 



(7) Fine pumiceous dust, from beds in Montana and Nebraska. 



(8) A series comprising 40 hand specimens illustrating the various 

 kinds of lavas, and also 2 large specimens of i)olished paleozoic lava 

 (felsite), from eastern Massachusetts. 



(0) Volcanic sublimation products, including sulphar, ammonium 

 chloride and iron oxides from various American and foreign sources. 



(10) Siliceous and calcareous sinters from the geysers aud hot springs 

 of the Yellowstone National Park, and travertines from extinct hot 

 springs in Arizona. The jjossible economy of volcanoes was illustrated 

 in the sulphur and other sublimation i)roducts, pozzuolaui (a natural 

 concrete) building-stone, and the beautiful "onyx marbles" or traver- 

 tines. 



II. GL.\CIEKS AND (JLACI.VL I'll HXC >MKN A. 



{(() Views illustrating living glaciers and icebergs. 



(6) A relief map of the United States, showing the theoretical resto- 

 ration of the ancient ice sheet at the stage of the Glacial period follow- 

 ing the Main Silt epoch. 



(c) A large series of photographs and other illustrations sliowing 

 characteristic glacial i>henomena, as below : 



(1) Views of glacial deposits, as moraines, drundins, and kames. 



(2) Views of large drift bowlders the source of which has been traced 

 with api)roximate accuracy. 



(3) Views of glaciated rock surfaces. 



{cl} Actual specimens illustrating the transporting and eroding 

 power of glaciers, as : 



^1) Specimens of glacial clays, sands, and drift bowlders. ()f])artic- 

 ular interest in this series are bowlders taken from various altitudes 

 in the White and Catskill mountains, and bowlders of i)eridotite and 

 other rocks in Phodc Island, Ohio, aud Illinois, the original source of 

 which is known with approximate accuracy. 



(2) Scratched and scarred bowlders from glacial till. 



(3) Scratched and scarred bowlders Irom glaciers still existing. 



(4) Glacial flour. 



