Jan., 1 92 1. Annual Report of the Director. 



397 



first, synoptic collections of gold, silver and lead minerals and ores and 

 secondly, collections of these ores geographically arranged. Platinum 

 ores occupy one table case at the head of the series. The gold, silver and 

 lead collections are followed by ores of the other metals with the speci- 

 mens geographically arranged under each metal. Interspersed with 

 these ores at convenient points are placed models illustrating methods 

 of mining and of extracting the metals from the ores. The metallurgy 

 of some of the more important metals is also illustrated by specimens. 

 Following the ore collections are placed those of the building stones and 

 marbles. These are shown in the form of polished slabs in upright cases 

 and of four-inch cubes in table cases. To them are added specimens of 

 materials adapted to ornamental uses cut in forms intended to display 

 their fitness for such uses. The western end of the hall is filled with a 

 variety of minerals of economic interest, including mica, asbestos, and 

 abrasive materials, and at the extreme end the alkali collections are 

 placed. The western hall, which is the largest of the exhibition halls of 

 the department, is devoted to the paleontological collections. This 

 hall, as already stated, is 48 feet in width and 317 feet in length. Its 

 size and proportions have enabled a imique installation of the paleonto- 

 logical collections to be made, the most important feature being that it 

 has been possible to place all the collections in the hall in chronological 

 order. Thus an epitome of the history of life upon the earth, beginning 

 with the remains of living forms of the earliest period and passing in 

 order to the life of Recent time is presented to the observer. The 

 characteristic fossils or life forms of any particular period can be seen in 

 whatever portion of the hall corresponds in position to the place of the 

 period in time, or the course and development of life as a whole can be 

 studied. The earlier forms have been placed at the south end of the hall, 

 and from this point the progression in time advances to the north end. 

 Introductory to the series, two cases contain, one a collection illustrating 

 methods of f ossilization and the other a collection sh/jwing contrasting 

 forms of ancient and modem plants and animals. As in the other 

 halls of the department, the cases in this hall are arranged to form 

 alcoves, the sides of the alcoves being made by upright cases twelve 

 feet in length by eight feet in height and usually two feet in depth. Two 

 of these placed back-to-back with ends resting against the pilasters 

 which separate the windows of the hall form the alcoves. Within these 

 alcoves for the most part, single sloping-top cases designed for specimens 

 which require close inspection are placed. These cases occupy a floor 

 space of four by five feet each, leaving an aisle three feet wide between 

 them and the sides of the alcoves and four feet wide between them and 

 the windows. Occasionally the alcove space is doubled or trebled in 



