CONTENTS 



Page 

 Introduction . ' 



History of discovery 3 



Resume of discoveries prior to 1907 3 



Recent discoveries 



Geologic distribution 



Geographic distribution 9 



Alberta 9 



Saskatchewan 13 



Montana 13 



North Dakota 14 



South Dakota 14 



Wyoming 1 ^ 



Colorado 16 



New Mexico '° 



Texas ' ' 



Mexico I** 



South America 1" 



Mongolia 1° 



British Columbia (footprints) 1° 



Alphabetical list of genera and species 19 



Ecology, habits and manner of life 20 



Environment ^U 



21 



Feeding habits 



22 

 Methods of combat 



Progressive evolutionary changes and phylogeny 24 



10 

 General morphology 



Monoclones (Centrosaurus) flexus 



Axial skeleton 



Skull 30 



Rostral 



32 

 Premaxillary 



Nasal 32 



Lacrvmal 



33 



Maxillary 



t i ' 33 

 Jugal 



