or is simply set against it. The fact that it does not con- 
tinue across the crater to the right, as seen in the drawing 
(plate 21, p. 38), proves nothing, as the rhyolite, which 
extends down the opposite spur to a point considerably below 
the base of the basalt, may have been deposited either before 
or after it. I had not time to go on with this interesting 
investigation or I should, without doubt, have been able to 
solve the whole problem of the relative ages of all the canyon 
rocks. 1 
Again on page 42 hejwrites: 
\ 
a 
'This valley (Junction Talley) is situated in one 
of the most interesting as well as one of the most beautiful 
regions in the park. The geologist might find a year's 
profitable work within a radius of ten miles about Baronett's 
Bridge, and the tourist could find almost unlimited so\irces 
of pleasure. Geographically there are illustrations of many 
most interesting problems of geological history and the very 
perplexing events of the volcanic Tertiary period may be 
studied to the best advantage. 
1 Forth of the valley lies the range of Granitic 
Mountains that must have looked down in succession upon the 
Eocene, Miocene, and Pliocene Lakes and witnessed the extra- 
ordinary events of the volcanic period. Here, during the 
latter part of the volcanic epoch while the subaerial deposits 
were in process of formation, the erosion seems to have been 
