226 KNOWLTON 



common to the Fort Union, while their Viburnum vitifolium is not 

 greatly different from our V. antiquum. Of common genera men- 

 tion may be made of the following: Celastrophyllum, Aralia, 

 Hedera, LitscBa, Hamamelites, Laurus, Cinnamomum, etc. 



Other affinities could be pointed out, but space will be taken only 

 for a brief conparison with the extensive plant deposits in North 

 Greenland. The age of these beds was at first considered by Heer 

 to be Miocene, but later students, among them Saporta, Gardner, 

 Ettingshausen and many others, have quite generally referred them 

 to the Eocene. There are many species in common with the Fort 

 Union, such as Sequoia langsdorfii, S. couttsia, Ginkgo adiantoides, 

 Taxodiuni distichum miocemmi, Glyptosirohus europcBus, Populus 

 arctica, P. glandidifera, Sparganium stygium, Corylus macquarrii, 

 Juglans nigella, Paliurus colombi, Grewia crenata, Platanus aceroides, 

 Diospyros hrachysepala, etc., etc. 



It is perhaps hardly necessary to add that there can be no doubt 

 as to reference of the European localities mentioned to the Eocene, 

 their position being fixed by various lines of evidence. 



2. INVERTEBRATE EVIDENCE. 



The invertebrates of the lower member of the Fort Union are 

 relatively much less numerous both in species and individuals than 

 are the plants, yet, fortunately, considerable collections have been 

 secured in the critical areas. By combining the list of species given 

 by Dr. T. W. Stanton^^ for the " Ceratops beds, " of Converse County, 

 Wyoming, with that given by Dr. R. P. WhitfiekP^ for the "Hell 

 Creek beds" of Montana, we have an aggregate of 49 forms. It 

 should be stated, however, that this total includes 8 unnamed but 

 supposed new species of Unio mentioned by Stanton as occurring 

 in the "Ceratops beds." The distribution of these invertebrates is 

 shown in the accompanying table: 



List of invertebrates from "Hell Creek" and "Ceratops beds." 



[In the list the species marked with an asterisk are found in the "Hell 

 Creek beds"; those marked with a dagger, in the "Ceratops beds." The 



^« Bull. Geol. Soc. Am., vol. 8, 1897, p. 135. 



^' Bull. Am. Mas. Nat. Hist., vol. 23, 1907, table facing p. 829. 



