126 REPORT OF NATIONAL MUSEUM, 1914. 
filled at all times. In view of the exceptional interest in the subject 
at this time, a special collection of radio-active material was brought 
together, and is attracting much attention. It consists of all suit- 
able specimens that were in the possession of the Museum, besides a 
number of others obtained for the purpose, and is arranged in a 
double American case, in which has also been placed a series of min- 
erals illustrating physical properties as an introduction to the study 
of the systematic collection. 
In the hall of applied geology a new exhibit of native copper, 
together with a small amount of naturally associated gangue min- 
erals, was installed in one floor upright case. The pieces range from 
small hand specimens of arborescent growth to large thin sheets over 
2 feet in diameter, and many grotesque forms are shown as well as 
specimens whose chief interest lies in the light they throw on the 
genesis and geologic associations of native copper. The two older 
cases devoted to copper now contain exhibits essentially of the com- 
pounds of this mineral. The general display of iron ores, compris- 
ing a little over 300 specimens, both domestic and foreign, was rear- 
ranged in three new wall cases, while that of the Tenth Census iron 
ores was enlarged and rearranged by species under States. The 
collection relating to the geology and mining industry of Leadville, 
Colo., was reorganized with such a selection and arrangement of 
rock and ore samples as will amply and systematically illustrate the 
subject as described in Emmons’ report on the Leadville district. 
A series of ore specimens of silver, cobalt and nickel minerals in 
their natural gangue associations, from Cobalt, Ontario, was installed 
in a large case. Some of these are cut and polished and serve excel- 
lently to illustrate the paragenesis of the ores of this locality. In 
the same case the geology of the Sudbury district, Ontario, is also 
illustrated by a group of hand specimens of granitic and ore-bearing 
basic intrusives. Some large and notable examples of ornamental 
ctones were added to the economic series, and the exhibit of natural 
substances used for abrasive purposes was much improved. 
In systematic geology, the meteorite collection was rearranged to 
fill one wall and one American case, the section from the Marengo 
Cave was installed in a more fitting manner, and a collection of 
varied imitative forms and one showing Indian laterites were added. 
In invertebrate paleontology the new installations comprised illus- 
trations of the more important and characteristic fossil corals in an 
American case, a similar collection of fossil Medusew, and smaller 
exhibits of fossil holothurians and echinoids. The crustaceans of 
the family Eurypteridx were rearranged to occupy the greater part 
of an upright metal case, and the final preparatory work and general 
restoring of the fossil crinoids in three upright cases were completed 
and permanent printed labels added. In vertebrate paleontology, 
