THE RESURRECTION OF THE GRAND CANYON OF 
THE YELLOWSTONE. 
O. T. JONES and R. M. FIELD. 
INTRODUCTION. 
During- the visit of the Princeton Summer School of Geology 
and Natural Resources to the Yellowstone Park in 1926, one 
of us (R.M.F.) observed cross-bedded sediments in the wall 
of the Yellowstone Canyon near Red Rock. This observation 
was made from a point on the opposite side of the gorge a 
short distance below Canyon Camp. Time did not permit a 
visit to the Red Rock, but the distant view of the sediments 
suggested that they lay behind Red Rock in a curved channel 
which was once part of an old meander. This fact suggested 
that there had been at least two cycles in the erosion of the 
canyon with a period of infilling between the first and second 
cycle. During the visit of the Summer School on July 5. 
1928, the authors tog*ether with Messrs. W. A. Johnston and 
Parks studied the stratified beds of the Red Rock locality, 
while other members of the party under the leadership of 
Dr. E. L. Perry discovered sediments on the Lower Falls trail 
within 40 to 50 feet above the bottom of the canyon. Further 
investigation by Jones, Field, and Johnston showed that there 
were other remnants of filled channels exposed in the canyon 
walls between the upper and lower falls. The evidence as a 
whole, taken in conjunction with the distribution of the glacial 
deposits, pointed very clearly to the fact that the present 
canyon of the Yellowstone follows pretty closely along the 
course of a previous canyon which must have been cut, 
dammed, and filled to the brim with sediments in preglacial 
times. At this stage in the investigation the party left the 
Park and the discussion was continued on the train, while 
travelling south. Careful examination of the geological map 
in the Yellowstone Park Folio led to the suggestion that the 
preglacial gorge of the Yellowstone River might have been 
dammed by lava flows. Hague has described certain basalt 
flows in the lower part of the “Grand” Canyon as interbedded 
with the Canyon conglomerates and underlying the rhyolites. 
It seemed probable, however, that the basalt flows mapped by 
Hague in the Yellowstone and Lamar River valleys did not 
underlie the rhyolite but were remnants of flows lying on the 
valley floors and perched on the valley sides. At Thermopolis 
