206 BERRY— LOWER EOCENE FLORA OF [April 25, 



The genus Paliurus Jussieu with only two existing species rang- 

 ing from southern Europe through southern Asia to China and Japan 

 was cosmopolitan in former times. Upwards of 40 fossil species 

 have been described. At least twelve are known from the Upper 

 Cretaceous, all confined to the North American region. There are 

 two each in the Raritan, Alagothy and Laramie, five in the Dakota 

 and one each in the Eutaw formation of Georgia, in West Greenland 

 and Vancouver Island. There are ten Eocene species also confined 

 to North America. Two of these are found in the Fort Union and 

 there are three each in the Denver, in western Greenland and in the 

 Wilcox. The leaves are not common in the Wilcox but the charac- 

 teristic peltate fruits are not uncommon. The oldest European 

 forms are two species in the Oligocene of France and there is a well 

 marked species in the Oligocene (Vicksburg group) of Louisiana. 

 The thirteen Miocene species are found in Asia (Siberia, Sachalin), 

 Europe (Switzerland, Baden, Germany, Bohemia, Italy, Styria and 

 France), and North America (Colorado and Oregon). The pres- 

 ence of numerous species of Paliurus in the Upper Cretaceous and 

 Eocene of North America and their absence on other continents be- 

 fore the Oligocene renders it very probable that the genus originated 

 in the western hemisphere. 



The genus Zisyphus Jussieu with about forty existing species 

 largely shrubs, often prostrate or scrambling, and rarely small trees, 

 is mostly Indo-Malayan in its distribution but is represented by a 

 few species in the tropics of eastern Asia, America, Africa and Aus- 

 tralia. There are over fifty known fossil species and as in the genus 

 Paliurus the ten Upper Cretaceous species are confined to North 

 America. They are found in the Raritan and Magothy formations 

 of New Jersey and Maryland, the Eutaw formation in Georgia, the 

 Tuscaloosa formation in Alabama, the Woodbine formation in Texas, 

 the Dakota sandstone of the West, the Patoot beds of Greenland 

 and the Upper Cretaceous of Alaska. There are about twenty 

 Eocene species including the two common and characteristic species 

 of the Wilcox and one in the overlying Qaiborne of the embayment 

 region, five in the Denver, three in the Fort Union, two in the Green 

 River, one in Alaska and one in West Greenland. There are two 



