PALÉOZOOLOGIE ET PALÉOPHYTOLOGIE 125 



des formes, de sorte que ce Travail est au fond un chapitre bien venu dans une 

 Monographie plus générale que nous promet M. Groves. 



G. DOLLFUS. 



Chancy, R. W., The Flora of the Eagle Greek Formation. Contrib. 

 Walk. Mus., t. II, no 5, 3 fig., XXII PI Chicago, 1920. 



Dr. Ghaney describes a collection of OUgocene plants which he had gathered 

 in the years 1916 and 1917 in the gorge of the Columbia River, in Oregon 

 and Washington. Collections of fossil plants were made in nineteen locahties, 

 ranging from the mouth of McCort Creek on the Oregon side of the gorge 

 to the foot of the cUffs at Red Bluff in Washington, seven miles distant. 

 The plant leaves were embedded in a volcanic congiomerate which is in most. 

 places indurated. 



The Eagle Creek flora comprises seventy-two species which fall into 

 thirty-eight gênera. Thèse in tum are distributed among twenty-four famiHes 

 and seventeen orders, only one of Pteridophytes The Gymnosperms also form 

 a very conspicuous part, being represented by only three species, one of which 

 is doubtful. The Angiosperms comprise nearly 95 % of the flora, and were 

 clearly as dominant during the Eagle Greek epoch as they are today. Of the 

 class of Monocolyledonse, there are only five species. Nearly 89 % of the flora is 

 included under Dicotyledonœ, and is strikingly similar to the modem flora 

 of the eastern United States. Practically ail the arborescent famihes are repre- 

 sented, and the similarity is carried to the gênera, and, even to the species 

 in some cases. 



The ecological composition of the flora indicates that Eagle Creek repre- 

 sents two distinct types of plants — the one, Xerophytic, including six species 

 whose modem représentatives are dwellers of dry ridges and uplands ; the 

 other, the Mesophytic, including nineteen species, whose modem relatives 

 are dwellers of moist valleys, and four species whose modem relatives live 

 in swamps or swampy valleys. There is a third type whose habitat ranges 

 from Xerophytic to Mesophytic. Dr. Ghaney draws varions conclusions indi- 

 cated by the lithological character ; and by the flora of the Eagle Greek 

 formation, fmds that there is a unity of conditions suggested by both factors. 

 Thèse conditions probably were brought about by a Xerophytic upland plant 

 association with Mesophytic tracts along the streams. The upland was dis- 

 sected by valleys with rather deep and narrow dimensions, and leaves 

 from the upland trees were transplanted and carried down into the valleys, 

 and mixed with those of the Mesophytic growing there. 



Regarding the température of the climate of the Eagle Greek epoch, the 

 prédominance of temperate famiUes in the flora is significant, and it is clear 

 that the Eagle Greek plants had a cUmate not essentially unhke that in the 

 northeastern part of the United States today. The abundance of Xerophytic 

 and Mesophytic oaks in the Eagle Greek flora is a factor of primary impor- 

 tance in the considération of thé moisture relations during the Eagle Greek 

 epoch. The présence of moisture requiring three forms indicates that in the 

 dépressions, the air was humid. This moisture was no doubt contributed 

 in large part by the streams occupying the valleys. On the other hand, the 



