THE HALL OF FOSSIL VERTEBRATES 



-\oyia, science). It tells us of a long period of time before Man 

 appeared, probably millions of years, during which Mammals of 

 great size and unfamiliar form were the dominant animals — of a 

 yet longer era before that, during which huge Reptiles were rulers 

 of earth, sea and air — and of other more ancient periods during 

 which Amphibians, Fish and Invertebrate animals held sway in 

 turn. Vertebrate Palaeontology deals only with the higher classes 

 of fossil animals, the Vertebrata, or those that have backbones 

 (fish, amphibians, reptiles, birds and mammals). For fossils of 

 this kind the Bad-Lands of the Western States are the richest 

 field, and from there came nearly all the specimens in this hall, 

 the greater part of which have been found within the last ten 

 years. The hall was opened in 1895. 1 At the time of writing, 

 thirty complete skeletons of extinct animals have been placed 

 on exhibition, besides many t'mes that number of skulls, limbs 

 and other imperfect spec mens. 



To give the visitor a clear idea of these extinct animals, the 

 skeletons usually have been removed entirely from the rock in 

 which they were found and have been mounted as much as pos- 

 sible like skeletons of modern animals ; their probable appearance 

 and habits are described by the labels and illustrated by water- 

 color restorations. The especial interest of the hall lies in the fact 

 that it shows so many of the data upon which are based the 

 theories of Evolution. The arrangement of the specimens is 

 intended to show the history or evolution of different races of 

 animals, chiefly in North America. All the specimens of one race 

 or kind of animal have been placed together, the most ancient first, 

 the most recent last. All the skeletons in this hall are those of ex- 

 tinct animals. 2 The Mastodon and Great Irish Deer are half -petri- 

 fied bone dug out of peat bogs. All the others are petrified (i. e., 

 they have been buried so long that they have been converted 

 from bone into stone), and have been chiseled out of the solid 

 rock. The Megatherium is a plaster cast, taken from bones from 



1 A brief history of the Department will be found in the number of this 

 Journal for November-December, 1901. 



li Four small skeletons, those of the Raccoon, Cat, Opossum and young 

 Lamb, have been placed in the cases near their extinct relatives, for comparison. 



