764 INDEX TO THE STEATIGEAPHY OF NOKTH AMEEICA. 



5. It is shown that the beds under consideration, being above an unconformity, can no 

 longer be considered as a part of the "conformable Cretaceous series" and hence are not 

 Laramie. 



6. It is shown that the two members of the Fort Union, although usually distinct litho- 

 logically, can not be separated structurally, sedimentation having beefn uninterrupted, except 

 locally. 



7. The paleontological elements of the lower member are considered at length, beginning 

 with the plants. It is shown that of the 84 species, 61 are common to the upper member and 

 only 11 species to the Laramie of Colorado, while 15 species are common to other American 

 Eocene and nine species to the Miocene. The Eocene age of the Fort Union is fixed by tying 

 its flora to that of various Old World beds of known Eocene position. 



8. The invertebrate evidence is shown to be in substantial accord with that of the plants, 

 there being only four of the 49 species common to the Colorado Laramie. All, with a single 

 possible exception, are fresh-water forms. 



9. It is shown that the vertebrates afford no positive evidence of Cretaceous age. That 

 the dinosaurs exhibit Cretaceous afEnities is not denied, since, being without known descend- 

 ants, it is possible to compare them only with their progenitors. It has been proved beyond 

 question that they survived the profound orogenic movement and attendant, physical break at 

 the top of the Laramie in the Denver Basin of Colorado, and lived on in Arapahoe and Denver 

 time, and it is shown that in the areas considered in this paper they passed over a similar ero- 

 sional interval and are found in association with the Fort Union flora, which is of Eocene age. 



10. The mammals of the lower Fort Union show very little relationship with Jurassic or 

 Cretaceous forms but find their closest afEnities with those of the Puerco and Torrejon, which 

 are of acknowledged Eocene age. 



11. The chelonians are shown to be of little value in their bearing on the age of the lower 

 Fort Union, especially when compared with the Judith River forms, which are evidently in 



confusion. 



12. It is held that the line between Cretaceous and Tertiary should be drawn at the top of 

 the true Laramie. 



13. The final conclusion is reached that the beds here considered ("Hell Creek beds," 

 "somber beds," "Ceratops beds," "Laramie" of many writers) are stratigraphically, struc- 

 turally, and paleontologically inseparable from the Fort Union, and are Eocene in age. 



See also A. C. Veatch *^° and Whitman Cross/* and later papers by Stanton, ™ 

 Knowlton,^^" and Leonard.'^^ 



K 10. BbGUE RIVER VALI<EY, OREGON. 



Diller ^^^ says : 



Coal occurs at numerous localities in the Rogue River vaUey of southwestern Oregon, 

 between the Cascade Mountains on the east and the Klamath Mountains, locally called the 

 Siskiyou Mountains, on the west. 



********* 



The Cascade Range, east of the coal belt, is made up mainly of Tertiary lavas; the Kla- 

 math Mountains, on the west, are composed of granular igneous rocks and a smaller proportion 

 of pre-Cretaceous sediments. 



The soft rocks in which the Rogue River valley has been cut are sandstones, shales, and 

 conglomerates. They dip generally eastward, extending beneath the lava fields of the Cascade 

 Range. The older sediments along the western border of the valley, by Bear Creek from the 

 Toll House to Ashland, Phoenix, and Jacksonville, are Cretaceous in age and do not contain 

 coal. The coal-bearing rocks lie east of Bear Creek as far north as Medford, but beyond that 

 point they overlap the Cretaceous rocks and occupy the whole northern portion of the Rogue 

 River valley. 



