REPORT OF THE SECRETARY. 35 



were acquired chiefly by exchanges and gifts. These include a 

 quantity of South American material comprising Bolivian tin and 

 tungsten ores, and rare copper minerals from Chile, secured by 

 Custodian F. L. Hess through Guggenheim Bros., New York City; 

 Messrs. L. L. Ellis and Don Stewart, Oruro, Bolivia; and Prof. 

 Joseph T. Singewald, of Johns Hopkins University. In addition 

 a representative series of ores from Argentina was presented by the 

 ambassador, Mr. Tomas A. Le Breton. 



Interesting additions were made to the exhibit of radioactive min- 

 erals, including carnotite, euxenite, torbernite, and uraninite. 



The meteorite collection was augmented by representatives of four 

 falls, Forsyth County, N. C; Chinautla, Guatemala; Troup, Tex.; 

 and Owens Valley, Calif. 



New and rare specimens were added to the mineral collection 

 chiefly through exchanges. An attractive suite of precious opal in 

 the matrix, ranging in color from the " black " opal to the pale, 

 opalescent tints, was presented by the Rainbow Ridge Mining Co., 

 operating in Humboldt County, Nev., and important additions to 

 the collection of cut gems were acquired through the Frances Lea 

 Chamberlain fund. 



The petrological collection was enriched by the extensive series 

 of igneous rocks from islands of the Pacific and Indian Oceans, col- 

 lected by the late Dr. Joseph P. Iddings and presented by his sister, 

 Mrs. Francis D. Cleveland. Including also the scientific portion of 

 Dr. Iddings's library as well as valuable collections assigned to other 

 departments of the Museum, this is considered one of the most not- 

 able accessions of the year. 



Accessions of paleontological material aggregate at least 50,000 

 specimens and include much material from foreign sources. Several 

 thousand specimens of Cambrian fossils, collected chiefly by Secre- 

 tary Walcott, and approximately 25,000 specimens of Silurian and 

 Devonian forms from Maine are also among the year's acquisitions. 



Vertebrate, remains of unusual interest and in large quantity were 

 obtained by Mr. J. W. Gidley, collecting in Arizona under the joint 

 auspices of the National Museum and United States Geological Sur- 

 vey. A portion of this, including a rare species of mastodon and a 

 large glyptodon, is sufficiently complete to afford material for 

 restoration and exhibition. 



New exhibits include two cases containing gem minerals in the 

 matrix, supplemental to the gem collection; an entirely new install- 

 ment of the exhibit illustrating radioactivity, and instructive and 

 showy biological series selected from the crinoid collection of Dr. 

 Frank Springer; skeletons of the unique horned dinosaur, Brachy- 

 ceratops montanensis, a wolverine, or Gulo, and a bear, and a bio- 

 logic series illustrating the evolution of fossil plants. 



