VOLUME XXVI NUMBER 7 



THE 



JOURNAL OF GEOLOGY 



OCTOBER-NOJ^EMBER igiS 



THE ECOLOGICAL SIGNIFICANCE OF THE EAGLE 

 CREEK FLORA OF THE COLUMBIA RIVER GORGE 



RALPH W. CHANEY 



University of Iowa 



Introduction 



Geographic Location and Topographic Features of the Columbia Gorge 



Geologic Relations of the Eagle Creek Formation 



The Ecological Composition of the Flora 



Physical Conditions during the Eagle Creek Epoch 



Conclusion 



INTRODUCTION 



§ During the seasons of 19 16 and 191 7 considerable collections 



of fossil plant material were made by the writer in the gorge of the 

 ^ Columbia River, in Oregon and Washington. It has been planned 

 "^ to present a complete report on this material, including a descrip- 

 tion of new forms, a discussion of the age of the flora, and a con- 

 sideration of its ecological significance. In view of the possible 

 interruption of this larger task a discussion of the ecological signifi- 

 cance of the flora is presented in advance of the fuller report. 



Acknowledgment is made to Dr. J H. Bretz, of the University 

 of Chicago, who first directed the writer's attention to this field, 

 and who is responsible for the discovery of one of the most important 

 plant-bearing deposits. I am indebted also to Dr. F. H. Knowlton 



577 



