HELL CREEK BEDS, CERATOPS BEDS AND EQUIVALENTS 225 



the introduction of the earh'er representatives of certain important 

 genera and species. For example, the Fort Union contains several 

 species (Onoclea sensibilis, Coryliis americana, Corylus rostrala, 

 etc.) now living, a condition not known to obtain in any earlier 

 American horizon, while others are so obviously close to living species 

 as to be separated with difficulty. 



Of the various Old World plant deposits containing identical or 

 closely related species, mention may first be made of the English 

 Eocene. Thus, from Ardtun in Mull, which is regarded by Gard- 

 ner as referable to the lower Eocene and approximately of the same 

 age as Gelinden, we have the following conifers common to the 

 Fort Union: Sequoia langsdorfii, Glyptostrohiis europcBus, Sequoia 

 couttsice, and Ginkgo adiantoides . Of the ferns from the same local- 

 ity, Filicites hehridicus Forbes [Onoclea hehridica Gard. and Ett.] 

 is identical with our Onoclea sensibilis fossilis, to which also is re- 

 ferred Woodwardites arcticus Heer, from Atanekerdluk, North 

 Greenland. Osmunda lignitum (Giebel) from Bornemouth is appar- 

 ently the same as Asplenium magnum Kn. Among the dicoty- 

 ledons of the British Eocene, mention may be made of their Plata- 

 nites hehridica, which is apparently the same as our great Platanus 

 nobilis, while among identical species are Corylus macquarrii, Pop- 

 ulus arctica, Populus richardsoni, etc., while many genera {e. g., 

 Cinchonidium, Diospyros, Sapindus, Bauhenia, Ulniiis, Ficus, 

 Juglans, Laurus, Celastrus, Elceodendron, Zizyphus, Leguminosites, 

 etc.) show related and in some cases identical species. 



From the well-known lower Eocene deposits of Sezanne in the 

 Paris Basin, the following species have been identified in our Fort 

 Union: Monimiopsis fraterna Sap., M. ambrosicEfolia Sap., and 

 Hamamelites f other gilloides .Sap., while Marchantia sezannensis 

 Brongn., is very close to M. pealei Kn.; Viburnum giganleum Sap., 

 to V. antiquum (Newb.) Hollick; Grewiopsis credneriafolia Sap., to 

 G. populifolia Ward; Celastrinites hartogianus Sap., to Elceodendron 

 polymorphum Ward, etc. Among common genera with related 

 species we have: Pterospermites, Aralia, Celastrinites, Zizyphus, 

 Cornus, Hedera, Laurus, Sassafras, Daphnogene, Populus, Ulmus, 

 etc. 



The lower Eocene deposits at Gelinden in Belgium, regarded as 

 about the same age as Sezanne, have Aralia looziana Sap. and Mar., 



