40 
smallest and oldest type which has thus far been discovered. 
It exhibits a canine tooth. 06. Aceratherium mite. This isa 
slightly larger type, in which the canine has disappeared. c. 
Aceratherium occidentale. This is a considerably larger type, in 
which the lateral incisors are becoming reduced. Probably has 
four toes. ad. Aceratheritum tridactylum. ‘This is a form repre- 
sented by a complete skeleton in the Museum. Has only three 
toes. ¢. Aceratherium platycephalum. This is a flat-headed 
Rhinoceros of very large size, and remotely related to the 
other forms. /. Diceratherium dakotense. This is apparently 
an ancestor of the line of Diceratherium or Rhinoceroses with 
horns placed side by side. 
183. RESTORATION OF THE SKELETON OF AGRIOCHOERUS. This 
is a very remarkable animal, the characters of which have only 
just been made known by the explorations of the American 
Museum and of Princeton College. The skull and dentition is 
like that of a herbivore, but the toes are clawed somewhat as 
in the carnivores. The restoration was under the direction of J. 
L. Wortman. 
DEPARTMENT OF GEOLOGY. 
In charge of Prof. J. J. Stevenson. 
184. Collection of ORES AND COUNTRY ROCKS, from the Sudbury 
Nickel Mines, Ontario. Collected (1894) and exhibited by J. 
F. Kemp and T. G. White. The ore bodies at Sudbury con- 
sist of nickeliferous pyrrhotite and of chalcopyrite, in dark dio- 
rites of Huronian age. They are on the outer portions of the 
intrusions of igneous rock and near the walls, which are granite, 
quartzite, etc. The ores are roasted and smelted to mattes and 
afterwards refined. The raw ores, the roasted ores, and the 
mattes are all illustrated. The district is now the chief source 
of nickel. 
(Twenty specimens.) 
185. Collection of ORES AND COUNTRY ROCK AND PHOTOGRAPHS, 
from the Gap Nickel Mine in Lancaster Co., Pa. Collected 
