CONTENTS, 



Page. 



Letter of transmission xx 



Proftice xxiii 



INTRODUCTION. 



Section I. 



The Tertiary Formations of the Central Region of the United States 1 



TliePiiorco- 4 



The Wasatcb iJ 



Tlie Bridger 11 



Tlie Uiuta 1^ 



The Wliite River 13 



The Loiip Forlv 16 



TheEquus Betls 19 



Section II. 



Thi; Horizontal Relations of the North Americ-vn Tertiaries with those of Europe. . '27 



r A KT FIRST. 



The Puerco, Wasatch, and Bridger Faun^ 40 



Pisces 49 



Ela.snioliranchi 49 



Xiphotrygon 49 



Xipbotrygon acutidens 50 



Ginglymodi 52 



Clastes 53 



Clastes anax 53 



atrox 54 



cycliferus 54 



ciiueatiis 55 



Hali'coniorphi .56 



Pappichtliys • 56 



Pappichtliys solerops 57 



liC'vis 58 



jjlicatns - 59 



corsoni 60 



Neniatogiuithi 61 



Rhineastes 62 



Rbineastps peltaUis 63 



sniithii 64 



c al vTis 65 



arcuatiia GG 



Taduhi.s 67 



Isospondy li 67 



xi 



5^5^0 



