Geology and Mineralogy. 



505 



Third mammal 

 phase. Con- 

 tinued physical 

 condition s 

 without new in- 

 ter migrations. 

 Eocene deposits 

 probably main- 

 ly of volcanic 

 origin. 



Transition to Oligocene and Upper 

 Eocene. Uinta or Uintatherium 

 beds. Up to 1,750 feet. Ter- 

 tiary genera 87 per cent; Creta- 

 ceous genera 13 per cent. 



Middle Eocene. Washakie or 

 Eobasileus beds, 500 feet. 



Middle Eocene. Bridger or Oro- 

 hippus beds. Up to 1,800 feet. 

 Modernized mammal genera 81 

 per cent; Cretaceous genera 19 

 per cent. 



Lower Eocene. Wind River or 

 Lambdothei'ium beds. Up to 

 1,400 feet. Modernized mammal 

 genera 63 per cent; Cretaceous 

 genera 37 per cent. 



Absolute 

 dissimilar- 

 ity between 

 America 

 and Europe. 



Bartonien. 



Bartonien. 

 Upper Lute- 

 tien in part. 



Lower Lute- 

 tien in part. 

 Ypresien. 



Second mammal 

 phase. First 

 decided migra- 

 tion of modern- 

 ized forms be- 

 tween America 

 and Europe. 



Lower Eocene. Wasatch or Cory- 

 phodon beds. Up to 2,500 feet. 

 Modernized mammal genera 42 

 per cent; Cretaceous genera 58 

 per cent. 



Ypresien. 

 Sparnacien. 



First mammal 

 phase. Archaic 

 or M e s o z o i c 

 forms. 



Basal Eocene. Torrejon or Panto- 

 lambda beds, 300 feet. European 

 connections seen in the similar 

 stages of development in America 

 and France. Modernized mam- 

 mal genera 4 per cent; Mesozoic 

 genera 96 per cent. 



Basal Eocene. Puerco or Poly- 

 mastodon beds, 500 feet. Meso- 

 zoic mammal genera 100 per 

 cent. 



Thanetien 



or 

 Cernaysien. 



Affinity 

 with Nosto- 

 stylops beds 

 of Patago- 

 nia. Creta- 

 ceous or Ba- 

 sal Eocene. 

 Intermigra- 

 tion late 

 Cretaceous. 



c. s. 



9. Gold Nuggets from N~ew Guinea. — Professor A. Liver- 

 sidge of Sydney describes two small gold nuggets from New 

 Guinea, which, after being polished and etched with aqua regia, 

 showed near the edges a clearly marked concentric structure. 

 This is regarded as probably indicating successive deposition in 

 the walls of the cavity analogous to that observed in agates. — 

 Boy. Soe. JV. S. W., xl, 161. 



