10 FOSSIL FLORA OF THE JOHN DAY BASIN, OREGON. Lbull. 204. 



When these plants were suhraitted to me for study, it was thought 

 possi))le to present their description, together with a revision of our 

 knowledge of the previously known forms, within a space sufficiently 

 small to permit the publication of the matter as an appendix to a 

 paper on the general geology of the area, then in preparation by 

 Dr. Merriam. But it soon became apparent that this could not be 

 adequately done within the space available, and a short preliminary 

 report was prepared for and published b}' Dr. Merriam. '^^ The results 

 of a complete restudj^ of all available fossil plant material from the 

 John Day Basin are now presented. 



1 wish to record my great indebtedness to Dr. Merriam, who not 

 only accompanied me at a considerable personal sacrifice on a trip 

 through the region in 1901, but placed unreservedl}^ at my disposal all 

 material bearing in an}^ way on the problem then in the paleontological 

 museum of the University of California. To Dr. Arthur HoUick I 

 am indebted for the loan of all material from the John Day region 

 belonging to Columbia University, and now deposited in the New 

 York Botanical Garden at Bronx Park. This material, together with 

 the rich collections belonging to the United States National Museum, 

 represents practicall}^ all now known to have come from the John Day 

 Basin. 



GEOGRAPHIC LOCATION AND TOPOGRAPHIC FEATURES. 



The John Day Basin is situated in the north-central portion of the 

 State of Oregon. It lies mainly in Grant County, but extends also 

 into the northeastern portion of Crook County and the southern por- 

 tions of Gilliam, Morrow, and Umatilla counties. It is rudely rectan- 

 gular in outline, and is almost completely surrounded by the Blue 

 Mountains, whose rugged eastern ridges rise to a height of over 6,000 

 feet, those to the west being lower and made up largely of Tertiary 

 lavas, which form regular and often flat-topped ridges. 



John Day River, with its numerous branches and tributaries, drain- 

 ing an area of approximately 10,000 square miles, has a general west- 

 ward course through the basin, which it leaves on its west side through 

 a gap between the north and south ranges of the Blue Mountains; 

 thence its course is north to the Columbia. 



When viewed from an eminence the basin presents a rough and 

 rugged appearance and bears abundant evidence of former volcanic 

 activity in the shape of ridges and plateaus, often several thousand 

 feet in height, made up of volcanic flows of various kinds, as well as 

 vast deposits of ashes, tuffs, and occasionally sands and gravels. 

 Around these ridges and plateaus the water courses have cut deep and 

 often narrow canj^ons, especially in the soft ashes and tuff's, but occa- 

 sionally also through the massive basalts, rhyolites, and andesites. 



a A contribution to the geology of the John Day Basin: Univ. Cal., Bull. Dept. Geol.,Vol. II, No. 9, 

 April. 1901, pp. 2G9-314. 



