noticed by any previous observers. Upon referring to 
Hayden’s Survey of the park in the twelfth annual report 
for the year 1878, we were surprised and delighted to find 
that Holmes in his excellent geological description of the 
northern portion of the park gives abundant evidence both 
written and pictorial that he had observed several of the 
important features given in detail later in our paper, and 
that he was on the verge of leaching the same conclusion as 
we do. We feel that we could not do better than to quote 
the following paragraphs from his paper. 
1 Something of the past history of this Valley 
can be learned from the facts here observed (at Jasper Creek, 
now shown on the map as Deep Creek) . A stream - whether 
the Yellowstone or not, no one can say with certainty - had 
cut down through the Tertiary strata to a depth of 600 feet 
below the top of the present valley, and about 400 feet 
above the bed of the present river. The lava has flowed 
into it, filling the valley to the depth of 200 feet or more. 
Whether this occurred before or after the flow of the rhyolite 
I am unable to say from any facts observed, although on 
general principles we would probably be safe in concluding 
that it is more recent. The debris at the ends and on the 
top of the mass of basalt make it difficult to say whether 
it passes beneath the rhyolite of the main wall of the canyoon 
