2 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Goldthwait, were enabled by the generous contributions from several 
friends of the geological department to spend five weeks in the plateaus 
north of the canyon. An abstract of their report has been published 
in the Journal of Geology and a fuller statement of their results will form 
a later member of this Bulletin. 
Our itinerary, shown by a broken line with numbers for dates on 
Figure 1, was as follows : — From Provo by rail to Marysvale, July 12 ; 
Marysvale by wagon to Kanab, July 13 to 17; Kanab, in saddle 
with wagon outfit, to Mt. Trumbull and the Colorado canyon at Toro- 
weap, July 18 to 21; on the esplanade of the canyon, July 22; from 
the canyon to Toquerville, July 23 to 29; about Toquerville with 
wagon, July 30 to August 5. On the latter date I left my companions 
at St. George to continue their study of the Toquerville district, and 
went by wagon and rail to Salt Lake City, and thence to Nevada and 
Oregon, as will be described in a later number of this Bulletin. 
The observations made in 1900 led to certain departures from conclu- 
sions previously published, especially as to the time of the production 
of the great north-south faults by which the plateau province is traversed. 
It was believed that the greater part of the faulting had been accom- 
plished before the uplift of the region by which the erosion of the Colorado 
canyon was initiated; that is, during the plateau cycle of erosion, so- 
called because the removal of a great thickness of rocks from the broad 
area of the plateaus north and south of the canyon was then effected 
(a,p.119). It was further thought that during the canyon cycle of erosion 
extensive areas of weak Permian rocks were stripped from the uplifted 
region while the Colorado river was corroding its canyon (p. 139) ; and 
it was suspected that the western boundary of the uplifted region lay 
along the line of the Grand wash fault, on which a relatively late move- 
ment, long after an earlier movement, served to place the plateau region 
on the east above the Basin region on the west (p. 148). 
The first of these conclusions will here be further substantiated ; but 
at the same time it will be shown that modern faulting of large amount 
has taken place on the Hurricane fault fifty miles and more north of 
the canyon. Additional evidence will be presented as to the stripping — 
of weak Permian strata from the plateaus north of the canyon during 
the canyon cycle. Perhaps the most important result of the summer’s 
work bears on the recent movement along the Grand wash fault, which 
is now promoted from the rank of a supposition to that of a reasonable 
certainty, as will appear from the work of my student companions. Sev- 
eral collateral problems are discussed, as appears in the table of contents. 
