74 FOURTH FLOOR, SOUTH PAVILION 
all of the skeletons exhibited in these halls are of animals which lived 
from 30,000 to 20,000,000 years ago. To prepare a specimen for 
exhibition the matrix in which the bones are imbedded is carefully chipped 
away and the missing parts restored in cement and plaster. The bones are 
then assembled as in life. In the specimens on exhibition the restored 
parts differ in color from the original parts of the skeleton and can readily 
be distinguished. 
As a whole, the Museum collections of fossil vertebrates are believed to 
be the finest in the world, if we take into consideration not merely numbers, 
but also variety, quality and perfected methods of preparation and ex- 
hibition. The collections illustrating the evolution of the horse are 
probably equal to those of all other institutions combined. The collec- 
tions of Permian reptiles, of Jurassic and Cretaceous dinosaurs, of turtles, 
of North American Tertiary mammals, and of extinct mammals of South 
America, are likewise of the first rank. There are more than seventy 
complete skeletons on exhibition, several hundred skulls and nearly two 
thousand jaws or other parts of various species. About ten times this 
number are in storage, reserved for study and research, or not yet prepared 
for exhibition. 
WEST CORRIDOR 
Fossit FISHLIKE LIZARDS 
Directly in front of the elevator is a wall case in which the most recently 
acquired specimens are placed. The cases attached to the wall near the 
stairway contain specimens of huge marine fishlike lizards, which show the 
tremendous pressure to which fossils are often subjected and the fragmentary 
condition in which they are found. 
SOUTH PAVILION 
MASTODONS AND MAMMOTHS 
The visitor should first enter the South Pavilion in which are shown the 
skeletons of mammoths and mastodons, the prehistoric relatives of the 
modern elephants, and of the curious and extraordinary extinct animals which 
inhabited South America in prehistoric times, 30,000 to 100,000 years ago. 
On the left is a series of modern skeletons illustrating the evolution of the 
horse under the hand of man. Here are such extremes as the Shetland pony, 


